Update requests to 2.18.4

lib/requests/exceptions.py

@@ -5,19 +5,17 @@ requests.exceptions
 ~~~~~~~~~~~~~~~~~~~
 
 This module contains the set of Requests' exceptions.
-
 """
-from .packages.urllib3.exceptions import HTTPError as BaseHTTPError
+from urllib3.exceptions import HTTPError as BaseHTTPError
 
 
 class RequestException(IOError):
     """There was an ambiguous exception that occurred while handling your
-    request."""
+    request.
+    """
 
     def __init__(self, *args, **kwargs):
-        """
-        Initialize RequestException with `request` and `response` objects.
-        """
+        """Initialize RequestException with `request` and `response` objects."""
         response = kwargs.pop('response', None)
         self.response = response
         self.request = kwargs.pop('request', None)
@@ -80,7 +78,11 @@ class InvalidSchema(RequestException, ValueError):
 
 
 class InvalidURL(RequestException, ValueError):
-    """ The URL provided was somehow invalid. """
+    """The URL provided was somehow invalid."""
+
+
+class InvalidHeader(RequestException, ValueError):
+    """The header value provided was somehow invalid."""
 
 
 class ChunkedEncodingError(RequestException):
@@ -99,6 +101,9 @@ class RetryError(RequestException):
     """Custom retries logic failed"""
 
 
+class UnrewindableBodyError(RequestException):
+    """Requests encountered an error when trying to rewind a body"""
+
 # Warnings
 
 
@@ -108,7 +113,10 @@ class RequestsWarning(Warning):
 
 
 class FileModeWarning(RequestsWarning, DeprecationWarning):
-    """
-    A file was opened in text mode, but Requests determined its binary length.
-    """
+    """A file was opened in text mode, but Requests determined its binary length."""
+    pass
+
+
+class RequestsDependencyWarning(RequestsWarning):
+    """An imported dependency doesn't match the expected version range."""
     pass