Remove Python 2 handling code (#2098)

* Remove Python 2 update modal

* Remove Python 2 handling code

* Remove backports dependencies

* Remove uses of future and __future__

* Fix import

* Remove requirements

* Update lib folder

* Clean up imports and blank lines

---------

Co-authored-by: JonnyWong16 <9099342+JonnyWong16@users.noreply.github.com>

lib/future/moves/_dummy_thread.py

@@ -1,8 +1,13 @@
 from __future__ import absolute_import
-from future.utils import PY3
+from future.utils import PY3, PY39_PLUS
 
-if PY3:
-    from _dummy_thread import *
+
+if PY39_PLUS:
+    # _dummy_thread and dummy_threading modules were both deprecated in
+    # Python 3.7 and removed in Python 3.9
+    from _thread import *
+elif PY3:
+        from _dummy_thread import *
 else:
     __future_module__ = True
     from dummy_thread import *

lib/future/moves/multiprocessing.py

@@ -0,0 +1,7 @@
+from __future__ import absolute_import
+from future.utils import PY3
+
+from multiprocessing import *
+if not PY3:
+    __future_module__ = True
+    from multiprocessing.queues import SimpleQueue

lib/future/moves/test/support.py

@@ -1,9 +1,18 @@
 from __future__ import absolute_import
+
+import sys
+
 from future.standard_library import suspend_hooks
 from future.utils import PY3
 
 if PY3:
     from test.support import *
+    if sys.version_info[:2] >= (3, 10):
+        from test.support.os_helper import (
+            EnvironmentVarGuard,
+            TESTFN,
+        )
+        from test.support.warnings_helper import check_warnings
 else:
     __future_module__ = True
     with suspend_hooks():