Revert "Remove Python 3.6 support"

This reverts commit 6929b41a21.

yt_dlp/compat/__init__.py

@@ -3,6 +3,7 @@ import sys
 import warnings
 import xml.etree.ElementTree as etree
 
+from . import re
 from ._deprecated import *  # noqa: F401, F403
 from .compat_utils import passthrough_module
 
@@ -32,7 +33,6 @@ compat_os_name = os._name if os.name == 'java' else os.name
 
 if compat_os_name == 'nt':
     def compat_shlex_quote(s):
-        import re
         return s if re.match(r'^[-_\w./]+$', s) else '"%s"' % s.replace('"', '\\"')
 else:
     from shlex import quote as compat_shlex_quote  # noqa: F401

yt_dlp/compat/_legacy.py

@@ -22,14 +22,10 @@ import urllib.request
 import xml.etree.ElementTree as etree
 from subprocess import DEVNULL
 
-# isort: split
-import asyncio  # noqa: F401
-import re  # noqa: F401
-from asyncio import run as compat_asyncio_run  # noqa: F401
-from re import Pattern as compat_Pattern  # noqa: F401
-from re import match as compat_Match  # noqa: F401
-
-from .compat_utils import passthrough_module
+from .compat_utils import passthrough_module  # isort: split
+from .asyncio import run as compat_asyncio_run  # noqa: F401
+from .re import Pattern as compat_Pattern  # noqa: F401
+from .re import match as compat_Match  # noqa: F401
 from ..dependencies import Cryptodome_AES as compat_pycrypto_AES  # noqa: F401
 from ..dependencies import brotli as compat_brotli  # noqa: F401
 from ..dependencies import websockets as compat_websockets  # noqa: F401

yt_dlp/compat/asyncio.py

@@ -0,0 +1,23 @@
+# flake8: noqa: F405
+from asyncio import *  # noqa: F403
+
+from .compat_utils import passthrough_module
+
+passthrough_module(__name__, 'asyncio')
+del passthrough_module
+
+try:
+    run  # >= 3.7
+except NameError:
+    def run(coro):
+        try:
+            loop = get_event_loop()
+        except RuntimeError:
+            loop = new_event_loop()
+            set_event_loop(loop)
+        loop.run_until_complete(coro)
+
+try:
+    all_tasks  # >= 3.7
+except NameError:
+    all_tasks = Task.all_tasks

yt_dlp/compat/re.py

@@ -0,0 +1,18 @@
+# flake8: noqa: F405
+from re import *  # F403
+
+from .compat_utils import passthrough_module
+
+passthrough_module(__name__, 're')
+del passthrough_module
+
+try:
+    Pattern  # >= 3.7
+except NameError:
+    Pattern = type(compile(''))
+
+
+try:
+    Match  # >= 3.7
+except NameError:
+    Match = type(compile('').match(''))