[cleanup] Remove unused code paths (#2173)

Notes:

* `_windows_write_string`: Fixed in 3.6
  * https://bugs.python.org/issue1602
  * PEP: https://www.python.org/dev/peps/pep-0528

* Windows UTF-8 fix: Fixed in 3.3
  * https://bugs.python.org/issue13216

* `__loader__`: is always present in 3.3+
  * https://bugs.python.org/issue14646

* `workaround_optparse_bug9161`: Fixed in 2.7
  * https://bugs.python.org/issue9161

Authored by: fstirlitz

yt_dlp/extractor/bpb.py

@@ -16,7 +16,6 @@ class BpbIE(InfoExtractor):
 
     _TEST = {
         'url': 'http://www.bpb.de/mediathek/297/joachim-gauck-zu-1989-und-die-erinnerung-an-die-ddr',
-        # md5 fails in Python 2.6 due to buggy server response and wrong handling of urllib2
         'md5': 'c4f84c8a8044ca9ff68bb8441d300b3f',
         'info_dict': {
             'id': '297',

yt_dlp/extractor/common.py

@@ -3606,9 +3606,7 @@ class InfoExtractor(object):
         for header, cookies in url_handle.headers.items():
             if header.lower() != 'set-cookie':
                 continue
-            if sys.version_info[0] >= 3:
-                cookies = cookies.encode('iso-8859-1')
-            cookies = cookies.decode('utf-8')
+            cookies = cookies.encode('iso-8859-1').decode('utf-8')
             cookie_value = re.search(
                 r'%s=(.+?);.*?\b[Dd]omain=(.+?)(?:[,;]|$)' % cookie, cookies)
             if cookie_value:

yt_dlp/extractor/commonmistakes.py

@@ -1,7 +1,5 @@
 from __future__ import unicode_literals
 
-import sys
-
 from .common import InfoExtractor
 from ..utils import ExtractorError
 
@@ -35,9 +33,7 @@ class UnicodeBOMIE(InfoExtractor):
     IE_DESC = False
     _VALID_URL = r'(?P<bom>\ufeff)(?P<id>.*)$'
 
-    # Disable test for python 3.2 since BOM is broken in re in this version
-    # (see https://github.com/ytdl-org/youtube-dl/issues/9751)
-    _TESTS = [] if (3, 0) < sys.version_info <= (3, 3) else [{
+    _TESTS = [{
         'url': '\ufeffhttp://www.youtube.com/watch?v=BaW_jenozKc',
         'only_matching': True,
     }]

yt_dlp/extractor/generic.py

@@ -4,7 +4,6 @@ from __future__ import unicode_literals
 
 import os
 import re
-import sys
 
 from .common import InfoExtractor
 from .youtube import YoutubeIE
@@ -4011,9 +4010,6 @@ class GenericIE(InfoExtractor):
                 # Look also in Refresh HTTP header
                 refresh_header = head_response.headers.get('Refresh')
                 if refresh_header:
-                    # In python 2 response HTTP headers are bytestrings
-                    if sys.version_info < (3, 0) and isinstance(refresh_header, str):
-                        refresh_header = refresh_header.decode('iso-8859-1')
                     found = re.search(REDIRECT_REGEX, refresh_header)
             if found:
                 new_url = compat_urlparse.urljoin(url, unescapeHTML(found.group(1)))