requirements/keys/helper/model: Move from mypy- to typing-extensions.

TypedDict requires an external module until Python 3.8;
typing-extensions is a newer equivalent of mypy-extensions that contains
types likely to be incorporated into typing in future version of Python.

Pipfile

@@ -9,7 +9,7 @@ zulip = ">=0.7.0"
 urwid-readline = ">=0.11"
 beautifulsoup4 = ">=4.9.0"
 lxml = ">=4.5.2"
-mypy_extensions = ">=0.4"
+typing_extensions = ">=3.7"
 
 [dev-packages]
 pytest = "==5.3.5"

requirements.txt

@@ -1,5 +1,7 @@
 urwid~=2.1.1
 zulip>=0.7.0
+typing_extensions>=3.7
+
 pytest==5.3.5
 pytest-cov==2.5.1
 pytest-mock==1.7.1

setup.py

@@ -110,6 +110,6 @@ def long_description():
         'urwid_readline>=0.11',
         'beautifulsoup4>=4.9.0',
         'lxml>=4.5.2',
-        'mypy_extensions>=0.4',
+        'typing_extensions>=3.7',
     ],
 )

zulipterminal/config/keys.py

@@ -1,7 +1,7 @@
 from collections import OrderedDict
 from typing import List, Set
 
-from mypy_extensions import TypedDict
+from typing_extensions import TypedDict
 
 
 KeyBinding = TypedDict('KeyBinding', {

zulipterminal/helper.py

@@ -13,7 +13,7 @@
 )
 
 import lxml.html
-from mypy_extensions import TypedDict
+from typing_extensions import TypedDict
 
 
 MACOS = platform.system() == "Darwin"

zulipterminal/model.py

@@ -9,7 +9,7 @@
 from urllib.parse import urlparse
 
 import zulip
-from mypy_extensions import TypedDict
+from typing_extensions import TypedDict
 
 from zulipterminal.config.keys import keys_for_command
 from zulipterminal.helper import (