[cleanup] Give up Python 2 compatiblity for setup.py

Change-Id: I2b0fab10e2005bcad95b9a1268dd0666f4fb2683
---
M pwb.py
M setup.py
2 files changed, 12 insertions(+), 7 deletions(-)

diff --git a/pwb.py b/pwb.py
index bb8e0c5..d5cd0e9 100755
--- a/pwb.py
+++ b/pwb.py
@@ -473,6 +473,8 @@
     # setup.py may also raise RuntimeError
     except RuntimeError as e:  # pragma: no cover
         sys.exit(e)
+    except SyntaxError as e:  # pragma: no cover
+        sys.exit(str(e) + '\nProbably outdated Python version')
 
     if not execute():
         print(__doc__)
diff --git a/setup.py b/setup.py
index 00a1cb9..fe66a45 100755
--- a/setup.py
+++ b/setup.py
@@ -1,5 +1,4 @@
 #!/usr/bin/python3
-# -*- coding: utf-8 -*-
 """Installer script for Pywikibot framework.
 
 **How to create a new distribution:**
@@ -25,11 +24,15 @@
 #
 # Distributed under the terms of the MIT license.
 #
-# ## KEEP PYTHON 2 SUPPORT FOR THIS SCRIPT ## #
 import os
 import re
 import sys
 
+if sys.version_info[:3] >= (3, 9):
+    List = list
+else:
+    from typing import List
+
 
 VERSIONS_REQUIRED_MESSAGE = """
 Pywikibot is not available on:
@@ -44,7 +47,7 @@
     raise RuntimeError(VERSIONS_REQUIRED_MESSAGE.format(version=sys.version))
 
 
-def python_is_supported():
+def python_is_supported() -> bool:
     """Check that Python is supported."""
     return sys.version_info[:3] >= (3, 5, 3)
 
@@ -147,7 +150,7 @@
 assert metadata.__name__ == name
 
 
-def get_validated_version():  # pragma: no cover
+def get_validated_version() -> str:  # pragma: no cover
     """Get a validated pywikibot module version string.
 
     The version number from pywikibot.__metadata__.__version__ is used.
@@ -205,7 +208,7 @@
     return version
 
 
-def read_desc(filename):  # pragma: no cover
+def read_desc(filename) -> str:  # pragma: no cover
     """Read long description.
 
     Combine included restructured text files which must be done before
@@ -227,7 +230,7 @@
     return ''.join(desc)
 
 
-def get_packages(name):  # pragma: no cover
+def get_packages(name) -> List[str]:  # pragma: no cover
     """Find framework packages."""
     try:
         from setuptools import find_namespace_packages
@@ -238,7 +241,7 @@
     return [str(name)] + packages
 
 
-def main():  # pragma: no cover
+def main() -> None:  # pragma: no cover
     """Setup entry point."""
     version = get_validated_version()
     setup(

