Update urllib3-1.26.7

lib/urllib3/packages/six.py

@@ -1,6 +1,4 @@
-"""Utilities for writing code that runs on Python 2 and 3"""
-
-# Copyright (c) 2010-2015 Benjamin Peterson
+# Copyright (c) 2010-2020 Benjamin Peterson
 #
 # Permission is hereby granted, free of charge, to any person obtaining a copy
 # of this software and associated documentation files (the "Software"), to deal
@@ -20,6 +18,8 @@
 # OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 # SOFTWARE.
 
+"""Utilities for writing code that runs on Python 2 and 3"""
+
 from __future__ import absolute_import
 
 import functools
@@ -29,7 +29,7 @@ import sys
 import types
 
 __author__ = "Benjamin Peterson <benjamin@python.org>"
-__version__ = "1.10.0"
+__version__ = "1.16.0"
 
 
 # Useful for very coarse version differentiation.
@@ -38,15 +38,15 @@ PY3 = sys.version_info[0] == 3
 PY34 = sys.version_info[0:2] >= (3, 4)
 
 if PY3:
-    string_types = str,
-    integer_types = int,
-    class_types = type,
+    string_types = (str,)
+    integer_types = (int,)
+    class_types = (type,)
     text_type = str
     binary_type = bytes
 
     MAXSIZE = sys.maxsize
 else:
-    string_types = basestring,
+    string_types = (basestring,)
     integer_types = (int, long)
     class_types = (type, types.ClassType)
     text_type = unicode
@@ -58,9 +58,9 @@ else:
     else:
         # It's possible to have sizeof(long) != sizeof(Py_ssize_t).
         class X(object):
-
             def __len__(self):
                 return 1 << 31
+
         try:
             len(X())
         except OverflowError:
@@ -71,6 +71,11 @@ else:
             MAXSIZE = int((1 << 63) - 1)
         del X
 
+if PY34:
+    from importlib.util import spec_from_loader
+else:
+    spec_from_loader = None
+
 
 def _add_doc(func, doc):
     """Add documentation to a function."""
@@ -84,7 +89,6 @@ def _import_module(name):
 
 
 class _LazyDescr(object):
-
     def __init__(self, name):
         self.name = name
 
@@ -101,7 +105,6 @@ class _LazyDescr(object):
 
 
 class MovedModule(_LazyDescr):
-
     def __init__(self, name, old, new=None):
         super(MovedModule, self).__init__(name)
         if PY3:
@@ -122,7 +125,6 @@ class MovedModule(_LazyDescr):
 
 
 class _LazyModule(types.ModuleType):
-
     def __init__(self, name):
         super(_LazyModule, self).__init__(name)
         self.__doc__ = self.__class__.__doc__
@@ -137,7 +139,6 @@ class _LazyModule(types.ModuleType):
 
 
 class MovedAttribute(_LazyDescr):
-
     def __init__(self, name, old_mod, new_mod, old_attr=None, new_attr=None):
         super(MovedAttribute, self).__init__(name)
         if PY3:
@@ -186,6 +187,11 @@ class _SixMetaPathImporter(object):
             return self
         return None
 
+    def find_spec(self, fullname, path, target=None):
+        if fullname in self.known_modules:
+            return spec_from_loader(fullname, self)
+        return None
+
     def __get_module(self, fullname):
         try:
             return self.known_modules[fullname]
@@ -221,28 +227,42 @@ class _SixMetaPathImporter(object):
         Required, if is_package is implemented"""
         self.__get_module(fullname)  # eventually raises ImportError
         return None
+
     get_source = get_code  # same as get_code
 
+    def create_module(self, spec):
+        return self.load_module(spec.name)
+
+    def exec_module(self, module):
+        pass
+
+
 _importer = _SixMetaPathImporter(__name__)
 
 
 class _MovedItems(_LazyModule):
 
     """Lazy loading of moved objects"""
+
     __path__ = []  # mark as package
 
 
 _moved_attributes = [
     MovedAttribute("cStringIO", "cStringIO", "io", "StringIO"),
     MovedAttribute("filter", "itertools", "builtins", "ifilter", "filter"),
-    MovedAttribute("filterfalse", "itertools", "itertools", "ifilterfalse", "filterfalse"),
+    MovedAttribute(
+        "filterfalse", "itertools", "itertools", "ifilterfalse", "filterfalse"
+    ),
     MovedAttribute("input", "__builtin__", "builtins", "raw_input", "input"),
     MovedAttribute("intern", "__builtin__", "sys"),
     MovedAttribute("map", "itertools", "builtins", "imap", "map"),
     MovedAttribute("getcwd", "os", "os", "getcwdu", "getcwd"),
     MovedAttribute("getcwdb", "os", "os", "getcwd", "getcwdb"),
+    MovedAttribute("getoutput", "commands", "subprocess"),
     MovedAttribute("range", "__builtin__", "builtins", "xrange", "range"),
-    MovedAttribute("reload_module", "__builtin__", "importlib" if PY34 else "imp", "reload"),
+    MovedAttribute(
+        "reload_module", "__builtin__", "importlib" if PY34 else "imp", "reload"
+    ),
     MovedAttribute("reduce", "__builtin__", "functools"),
     MovedAttribute("shlex_quote", "pipes", "shlex", "quote"),
     MovedAttribute("StringIO", "StringIO", "io"),
@@ -251,21 +271,36 @@ _moved_attributes = [
     MovedAttribute("UserString", "UserString", "collections"),
     MovedAttribute("xrange", "__builtin__", "builtins", "xrange", "range"),
     MovedAttribute("zip", "itertools", "builtins", "izip", "zip"),
-    MovedAttribute("zip_longest", "itertools", "itertools", "izip_longest", "zip_longest"),
+    MovedAttribute(
+        "zip_longest", "itertools", "itertools", "izip_longest", "zip_longest"
+    ),
     MovedModule("builtins", "__builtin__"),
     MovedModule("configparser", "ConfigParser"),
+    MovedModule(
+        "collections_abc",
+        "collections",
+        "collections.abc" if sys.version_info >= (3, 3) else "collections",
+    ),
     MovedModule("copyreg", "copy_reg"),
     MovedModule("dbm_gnu", "gdbm", "dbm.gnu"),
-    MovedModule("_dummy_thread", "dummy_thread", "_dummy_thread"),
+    MovedModule("dbm_ndbm", "dbm", "dbm.ndbm"),
+    MovedModule(
+        "_dummy_thread",
+        "dummy_thread",
+        "_dummy_thread" if sys.version_info < (3, 9) else "_thread",
+    ),
     MovedModule("http_cookiejar", "cookielib", "http.cookiejar"),
     MovedModule("http_cookies", "Cookie", "http.cookies"),
     MovedModule("html_entities", "htmlentitydefs", "html.entities"),
     MovedModule("html_parser", "HTMLParser", "html.parser"),
     MovedModule("http_client", "httplib", "http.client"),
-    MovedModule("email_mime_multipart", "email.MIMEMultipart", "email.mime.multipart"),
-    MovedModule("email_mime_nonmultipart", "email.MIMENonMultipart", "email.mime.nonmultipart"),
-    MovedModule("email_mime_text", "email.MIMEText", "email.mime.text"),
     MovedModule("email_mime_base", "email.MIMEBase", "email.mime.base"),
+    MovedModule("email_mime_image", "email.MIMEImage", "email.mime.image"),
+    MovedModule("email_mime_multipart", "email.MIMEMultipart", "email.mime.multipart"),
+    MovedModule(
+        "email_mime_nonmultipart", "email.MIMENonMultipart", "email.mime.nonmultipart"
+    ),
+    MovedModule("email_mime_text", "email.MIMEText", "email.mime.text"),
     MovedModule("BaseHTTPServer", "BaseHTTPServer", "http.server"),
     MovedModule("CGIHTTPServer", "CGIHTTPServer", "http.server"),
     MovedModule("SimpleHTTPServer", "SimpleHTTPServer", "http.server"),
@@ -283,15 +318,12 @@ _moved_attributes = [
     MovedModule("tkinter_ttk", "ttk", "tkinter.ttk"),
     MovedModule("tkinter_constants", "Tkconstants", "tkinter.constants"),
     MovedModule("tkinter_dnd", "Tkdnd", "tkinter.dnd"),
-    MovedModule("tkinter_colorchooser", "tkColorChooser",
-                "tkinter.colorchooser"),
-    MovedModule("tkinter_commondialog", "tkCommonDialog",
-                "tkinter.commondialog"),
+    MovedModule("tkinter_colorchooser", "tkColorChooser", "tkinter.colorchooser"),
+    MovedModule("tkinter_commondialog", "tkCommonDialog", "tkinter.commondialog"),
     MovedModule("tkinter_tkfiledialog", "tkFileDialog", "tkinter.filedialog"),
     MovedModule("tkinter_font", "tkFont", "tkinter.font"),
     MovedModule("tkinter_messagebox", "tkMessageBox", "tkinter.messagebox"),
-    MovedModule("tkinter_tksimpledialog", "tkSimpleDialog",
-                "tkinter.simpledialog"),
+    MovedModule("tkinter_tksimpledialog", "tkSimpleDialog", "tkinter.simpledialog"),
     MovedModule("urllib_parse", __name__ + ".moves.urllib_parse", "urllib.parse"),
     MovedModule("urllib_error", __name__ + ".moves.urllib_error", "urllib.error"),
     MovedModule("urllib", __name__ + ".moves.urllib", __name__ + ".moves.urllib"),
@@ -337,10 +369,14 @@ _urllib_parse_moved_attributes = [
     MovedAttribute("quote_plus", "urllib", "urllib.parse"),
     MovedAttribute("unquote", "urllib", "urllib.parse"),
     MovedAttribute("unquote_plus", "urllib", "urllib.parse"),
+    MovedAttribute(
+        "unquote_to_bytes", "urllib", "urllib.parse", "unquote", "unquote_to_bytes"
+    ),
     MovedAttribute("urlencode", "urllib", "urllib.parse"),
     MovedAttribute("splitquery", "urllib", "urllib.parse"),
     MovedAttribute("splittag", "urllib", "urllib.parse"),
     MovedAttribute("splituser", "urllib", "urllib.parse"),
+    MovedAttribute("splitvalue", "urllib", "urllib.parse"),
     MovedAttribute("uses_fragment", "urlparse", "urllib.parse"),
     MovedAttribute("uses_netloc", "urlparse", "urllib.parse"),
     MovedAttribute("uses_params", "urlparse", "urllib.parse"),
@@ -353,8 +389,11 @@ del attr
 
 Module_six_moves_urllib_parse._moved_attributes = _urllib_parse_moved_attributes
 
-_importer._add_module(Module_six_moves_urllib_parse(__name__ + ".moves.urllib_parse"),
-                      "moves.urllib_parse", "moves.urllib.parse")
+_importer._add_module(
+    Module_six_moves_urllib_parse(__name__ + ".moves.urllib_parse"),
+    "moves.urllib_parse",
+    "moves.urllib.parse",
+)
 
 
 class Module_six_moves_urllib_error(_LazyModule):
@@ -373,8 +412,11 @@ del attr
 
 Module_six_moves_urllib_error._moved_attributes = _urllib_error_moved_attributes
 
-_importer._add_module(Module_six_moves_urllib_error(__name__ + ".moves.urllib.error"),
-                      "moves.urllib_error", "moves.urllib.error")
+_importer._add_module(
+    Module_six_moves_urllib_error(__name__ + ".moves.urllib.error"),
+    "moves.urllib_error",
+    "moves.urllib.error",
+)
 
 
 class Module_six_moves_urllib_request(_LazyModule):
@@ -416,6 +458,8 @@ _urllib_request_moved_attributes = [
     MovedAttribute("URLopener", "urllib", "urllib.request"),
     MovedAttribute("FancyURLopener", "urllib", "urllib.request"),
     MovedAttribute("proxy_bypass", "urllib", "urllib.request"),
+    MovedAttribute("parse_http_list", "urllib2", "urllib.request"),
+    MovedAttribute("parse_keqv_list", "urllib2", "urllib.request"),
 ]
 for attr in _urllib_request_moved_attributes:
     setattr(Module_six_moves_urllib_request, attr.name, attr)
@@ -423,8 +467,11 @@ del attr
 
 Module_six_moves_urllib_request._moved_attributes = _urllib_request_moved_attributes
 
-_importer._add_module(Module_six_moves_urllib_request(__name__ + ".moves.urllib.request"),
-                      "moves.urllib_request", "moves.urllib.request")
+_importer._add_module(
+    Module_six_moves_urllib_request(__name__ + ".moves.urllib.request"),
+    "moves.urllib_request",
+    "moves.urllib.request",
+)
 
 
 class Module_six_moves_urllib_response(_LazyModule):
@@ -444,8 +491,11 @@ del attr
 
 Module_six_moves_urllib_response._moved_attributes = _urllib_response_moved_attributes
 
-_importer._add_module(Module_six_moves_urllib_response(__name__ + ".moves.urllib.response"),
-                      "moves.urllib_response", "moves.urllib.response")
+_importer._add_module(
+    Module_six_moves_urllib_response(__name__ + ".moves.urllib.response"),
+    "moves.urllib_response",
+    "moves.urllib.response",
+)
 
 
 class Module_six_moves_urllib_robotparser(_LazyModule):
@@ -460,15 +510,21 @@ for attr in _urllib_robotparser_moved_attributes:
     setattr(Module_six_moves_urllib_robotparser, attr.name, attr)
 del attr
 
-Module_six_moves_urllib_robotparser._moved_attributes = _urllib_robotparser_moved_attributes
+Module_six_moves_urllib_robotparser._moved_attributes = (
+    _urllib_robotparser_moved_attributes
+)
 
-_importer._add_module(Module_six_moves_urllib_robotparser(__name__ + ".moves.urllib.robotparser"),
-                      "moves.urllib_robotparser", "moves.urllib.robotparser")
+_importer._add_module(
+    Module_six_moves_urllib_robotparser(__name__ + ".moves.urllib.robotparser"),
+    "moves.urllib_robotparser",
+    "moves.urllib.robotparser",
+)
 
 
 class Module_six_moves_urllib(types.ModuleType):
 
     """Create a six.moves.urllib namespace that resembles the Python 3 namespace"""
+
     __path__ = []  # mark as package
     parse = _importer._get_module("moves.urllib_parse")
     error = _importer._get_module("moves.urllib_error")
@@ -477,10 +533,12 @@ class Module_six_moves_urllib(types.ModuleType):
     robotparser = _importer._get_module("moves.urllib_robotparser")
 
     def __dir__(self):
-        return ['parse', 'error', 'request', 'response', 'robotparser']
+        return ["parse", "error", "request", "response", "robotparser"]
 
-_importer._add_module(Module_six_moves_urllib(__name__ + ".moves.urllib"),
-                      "moves.urllib")
+
+_importer._add_module(
+    Module_six_moves_urllib(__name__ + ".moves.urllib"), "moves.urllib"
+)
 
 
 def add_move(move):
@@ -520,19 +578,24 @@ else:
 try:
     advance_iterator = next
 except NameError:
+
     def advance_iterator(it):
         return it.next()
+
+
 next = advance_iterator
 
 
 try:
     callable = callable
 except NameError:
+
     def callable(obj):
         return any("__call__" in klass.__dict__ for klass in type(obj).__mro__)
 
 
 if PY3:
+
     def get_unbound_function(unbound):
         return unbound
 
@@ -543,6 +606,7 @@ if PY3:
 
     Iterator = object
 else:
+
     def get_unbound_function(unbound):
         return unbound.im_func
 
@@ -553,13 +617,13 @@ else:
         return types.MethodType(func, None, cls)
 
     class Iterator(object):
-
         def next(self):
             return type(self).__next__(self)
 
     callable = callable
-_add_doc(get_unbound_function,
-         """Get the function out of a possibly unbound function""")
+_add_doc(
+    get_unbound_function, """Get the function out of a possibly unbound function"""
+)
 
 
 get_method_function = operator.attrgetter(_meth_func)
@@ -571,6 +635,7 @@ get_function_globals = operator.attrgetter(_func_globals)
 
 
 if PY3:
+
     def iterkeys(d, **kw):
         return iter(d.keys(**kw))
 
@@ -589,6 +654,7 @@ if PY3:
 
     viewitems = operator.methodcaller("items")
 else:
+
     def iterkeys(d, **kw):
         return d.iterkeys(**kw)
 
@@ -609,42 +675,52 @@ else:
 
 _add_doc(iterkeys, "Return an iterator over the keys of a dictionary.")
 _add_doc(itervalues, "Return an iterator over the values of a dictionary.")
-_add_doc(iteritems,
-         "Return an iterator over the (key, value) pairs of a dictionary.")
-_add_doc(iterlists,
-         "Return an iterator over the (key, [values]) pairs of a dictionary.")
+_add_doc(iteritems, "Return an iterator over the (key, value) pairs of a dictionary.")
+_add_doc(
+    iterlists, "Return an iterator over the (key, [values]) pairs of a dictionary."
+)
 
 
 if PY3:
+
     def b(s):
         return s.encode("latin-1")
 
     def u(s):
         return s
+
     unichr = chr
     import struct
+
     int2byte = struct.Struct(">B").pack
     del struct
     byte2int = operator.itemgetter(0)
     indexbytes = operator.getitem
     iterbytes = iter
     import io
+
     StringIO = io.StringIO
     BytesIO = io.BytesIO
+    del io
     _assertCountEqual = "assertCountEqual"
     if sys.version_info[1] <= 1:
         _assertRaisesRegex = "assertRaisesRegexp"
         _assertRegex = "assertRegexpMatches"
+        _assertNotRegex = "assertNotRegexpMatches"
     else:
         _assertRaisesRegex = "assertRaisesRegex"
         _assertRegex = "assertRegex"
+        _assertNotRegex = "assertNotRegex"
 else:
+
     def b(s):
         return s
+
     # Workaround for standalone backslash
 
     def u(s):
-        return unicode(s.replace(r'\\', r'\\\\'), "unicode_escape")
+        return unicode(s.replace(r"\\", r"\\\\"), "unicode_escape")
+
     unichr = unichr
     int2byte = chr
 
@@ -653,12 +729,15 @@ else:
 
     def indexbytes(buf, i):
         return ord(buf[i])
+
     iterbytes = functools.partial(itertools.imap, ord)
     import StringIO
+
     StringIO = BytesIO = StringIO.StringIO
     _assertCountEqual = "assertItemsEqual"
     _assertRaisesRegex = "assertRaisesRegexp"
     _assertRegex = "assertRegexpMatches"
+    _assertNotRegex = "assertNotRegexpMatches"
 _add_doc(b, """Byte literal""")
 _add_doc(u, """Text literal""")
 
@@ -675,17 +754,27 @@ def assertRegex(self, *args, **kwargs):
     return getattr(self, _assertRegex)(*args, **kwargs)
 
 
+def assertNotRegex(self, *args, **kwargs):
+    return getattr(self, _assertNotRegex)(*args, **kwargs)
+
+
 if PY3:
     exec_ = getattr(moves.builtins, "exec")
 
     def reraise(tp, value, tb=None):
-        if value is None:
-            value = tp()
-        if value.__traceback__ is not tb:
-            raise value.with_traceback(tb)
-        raise value
+        try:
+            if value is None:
+                value = tp()
+            if value.__traceback__ is not tb:
+                raise value.with_traceback(tb)
+            raise value
+        finally:
+            value = None
+            tb = None
+
 
 else:
+
     def exec_(_code_, _globs_=None, _locs_=None):
         """Execute code in a namespace."""
         if _globs_ is None:
@@ -696,30 +785,36 @@ else:
             del frame
         elif _locs_ is None:
             _locs_ = _globs_
-        exec("""exec _code_ in _globs_, _locs_""")
+        exec ("""exec _code_ in _globs_, _locs_""")
 
-    exec_("""def reraise(tp, value, tb=None):
-    raise tp, value, tb
-""")
+    exec_(
+        """def reraise(tp, value, tb=None):
+    try:
+        raise tp, value, tb
+    finally:
+        tb = None
+"""
+    )
 
 
-if sys.version_info[:2] == (3, 2):
-    exec_("""def raise_from(value, from_value):
-    if from_value is None:
-        raise value
-    raise value from from_value
-""")
-elif sys.version_info[:2] > (3, 2):
-    exec_("""def raise_from(value, from_value):
-    raise value from from_value
-""")
+if sys.version_info[:2] > (3,):
+    exec_(
+        """def raise_from(value, from_value):
+    try:
+        raise value from from_value
+    finally:
+        value = None
+"""
+    )
 else:
+
     def raise_from(value, from_value):
         raise value
 
 
 print_ = getattr(moves.builtins, "print", None)
 if print_ is None:
+
     def print_(*args, **kwargs):
         """The new-style print function for Python 2.4 and 2.5."""
         fp = kwargs.pop("file", sys.stdout)
@@ -730,14 +825,17 @@ if print_ is None:
             if not isinstance(data, basestring):
                 data = str(data)
             # If the file has an encoding, encode unicode with it.
-            if (isinstance(fp, file) and
-                    isinstance(data, unicode) and
-                    fp.encoding is not None):
+            if (
+                isinstance(fp, file)
+                and isinstance(data, unicode)
+                and fp.encoding is not None
+            ):
                 errors = getattr(fp, "errors", None)
                 if errors is None:
                     errors = "strict"
                 data = data.encode(fp.encoding, errors)
             fp.write(data)
+
         want_unicode = False
         sep = kwargs.pop("sep", None)
         if sep is not None:
@@ -773,6 +871,8 @@ if print_ is None:
                 write(sep)
             write(arg)
         write(end)
+
+
 if sys.version_info[:2] < (3, 3):
     _print = print_
 
@@ -783,16 +883,46 @@ if sys.version_info[:2] < (3, 3):
         if flush and fp is not None:
             fp.flush()
 
+
 _add_doc(reraise, """Reraise an exception.""")
 
 if sys.version_info[0:2] < (3, 4):
-    def wraps(wrapped, assigned=functools.WRAPPER_ASSIGNMENTS,
-              updated=functools.WRAPPER_UPDATES):
-        def wrapper(f):
-            f = functools.wraps(wrapped, assigned, updated)(f)
-            f.__wrapped__ = wrapped
-            return f
+    # This does exactly the same what the :func:`py3:functools.update_wrapper`
+    # function does on Python versions after 3.2. It sets the ``__wrapped__``
+    # attribute on ``wrapper`` object and it doesn't raise an error if any of
+    # the attributes mentioned in ``assigned`` and ``updated`` are missing on
+    # ``wrapped`` object.
+    def _update_wrapper(
+        wrapper,
+        wrapped,
+        assigned=functools.WRAPPER_ASSIGNMENTS,
+        updated=functools.WRAPPER_UPDATES,
+    ):
+        for attr in assigned:
+            try:
+                value = getattr(wrapped, attr)
+            except AttributeError:
+                continue
+            else:
+                setattr(wrapper, attr, value)
+        for attr in updated:
+            getattr(wrapper, attr).update(getattr(wrapped, attr, {}))
+        wrapper.__wrapped__ = wrapped
         return wrapper
+
+    _update_wrapper.__doc__ = functools.update_wrapper.__doc__
+
+    def wraps(
+        wrapped,
+        assigned=functools.WRAPPER_ASSIGNMENTS,
+        updated=functools.WRAPPER_UPDATES,
+    ):
+        return functools.partial(
+            _update_wrapper, wrapped=wrapped, assigned=assigned, updated=updated
+        )
+
+    wraps.__doc__ = functools.wraps.__doc__
+
 else:
     wraps = functools.wraps
 
@@ -802,44 +932,121 @@ def with_metaclass(meta, *bases):
     # This requires a bit of explanation: the basic idea is to make a dummy
     # metaclass for one level of class instantiation that replaces itself with
     # the actual metaclass.
-    class metaclass(meta):
-
+    class metaclass(type):
         def __new__(cls, name, this_bases, d):
-            return meta(name, bases, d)
-    return type.__new__(metaclass, 'temporary_class', (), {})
+            if sys.version_info[:2] >= (3, 7):
+                # This version introduced PEP 560 that requires a bit
+                # of extra care (we mimic what is done by __build_class__).
+                resolved_bases = types.resolve_bases(bases)
+                if resolved_bases is not bases:
+                    d["__orig_bases__"] = bases
+            else:
+                resolved_bases = bases
+            return meta(name, resolved_bases, d)
+
+        @classmethod
+        def __prepare__(cls, name, this_bases):
+            return meta.__prepare__(name, bases)
+
+    return type.__new__(metaclass, "temporary_class", (), {})
 
 
 def add_metaclass(metaclass):
     """Class decorator for creating a class with a metaclass."""
+
     def wrapper(cls):
         orig_vars = cls.__dict__.copy()
-        slots = orig_vars.get('__slots__')
+        slots = orig_vars.get("__slots__")
         if slots is not None:
             if isinstance(slots, str):
                 slots = [slots]
             for slots_var in slots:
                 orig_vars.pop(slots_var)
-        orig_vars.pop('__dict__', None)
-        orig_vars.pop('__weakref__', None)
+        orig_vars.pop("__dict__", None)
+        orig_vars.pop("__weakref__", None)
+        if hasattr(cls, "__qualname__"):
+            orig_vars["__qualname__"] = cls.__qualname__
         return metaclass(cls.__name__, cls.__bases__, orig_vars)
+
     return wrapper
 
 
+def ensure_binary(s, encoding="utf-8", errors="strict"):
+    """Coerce **s** to six.binary_type.
+
+    For Python 2:
+      - `unicode` -> encoded to `str`
+      - `str` -> `str`
+
+    For Python 3:
+      - `str` -> encoded to `bytes`
+      - `bytes` -> `bytes`
+    """
+    if isinstance(s, binary_type):
+        return s
+    if isinstance(s, text_type):
+        return s.encode(encoding, errors)
+    raise TypeError("not expecting type '%s'" % type(s))
+
+
+def ensure_str(s, encoding="utf-8", errors="strict"):
+    """Coerce *s* to `str`.
+
+    For Python 2:
+      - `unicode` -> encoded to `str`
+      - `str` -> `str`
+
+    For Python 3:
+      - `str` -> `str`
+      - `bytes` -> decoded to `str`
+    """
+    # Optimization: Fast return for the common case.
+    if type(s) is str:
+        return s
+    if PY2 and isinstance(s, text_type):
+        return s.encode(encoding, errors)
+    elif PY3 and isinstance(s, binary_type):
+        return s.decode(encoding, errors)
+    elif not isinstance(s, (text_type, binary_type)):
+        raise TypeError("not expecting type '%s'" % type(s))
+    return s
+
+
+def ensure_text(s, encoding="utf-8", errors="strict"):
+    """Coerce *s* to six.text_type.
+
+    For Python 2:
+      - `unicode` -> `unicode`
+      - `str` -> `unicode`
+
+    For Python 3:
+      - `str` -> `str`
+      - `bytes` -> decoded to `str`
+    """
+    if isinstance(s, binary_type):
+        return s.decode(encoding, errors)
+    elif isinstance(s, text_type):
+        return s
+    else:
+        raise TypeError("not expecting type '%s'" % type(s))
+
+
 def python_2_unicode_compatible(klass):
     """
-    A decorator that defines __unicode__ and __str__ methods under Python 2.
+    A class decorator that defines __unicode__ and __str__ methods under Python 2.
     Under Python 3 it does nothing.
 
     To support Python 2 and 3 with a single code base, define a __str__ method
     returning text and apply this decorator to the class.
     """
     if PY2:
-        if '__str__' not in klass.__dict__:
-            raise ValueError("@python_2_unicode_compatible cannot be applied "
-                             "to %s because it doesn't define __str__()." %
-                             klass.__name__)
+        if "__str__" not in klass.__dict__:
+            raise ValueError(
+                "@python_2_unicode_compatible cannot be applied "
+                "to %s because it doesn't define __str__()." % klass.__name__
+            )
         klass.__unicode__ = klass.__str__
-        klass.__str__ = lambda self: self.__unicode__().encode('utf-8')
+        klass.__str__ = lambda self: self.__unicode__().encode("utf-8")
     return klass
 
 
@@ -859,8 +1066,10 @@ if sys.meta_path:
         # be floating around. Therefore, we can't use isinstance() to check for
         # the six meta path importer, since the other six instance will have
         # inserted an importer with different class.
-        if (type(importer).__name__ == "_SixMetaPathImporter" and
-                importer.name == __name__):
+        if (
+            type(importer).__name__ == "_SixMetaPathImporter"
+            and importer.name == __name__
+        ):
             del sys.meta_path[i]
             break
     del i, importer