[cleanup] Upgrade syntax

Using https://github.com/asottile/pyupgrade

1. `__future__` imports and `coding: utf-8` were removed
2. Files were rewritten with `pyupgrade --py36-plus --keep-percent-format`
3. f-strings were cherry-picked from `pyupgrade --py36-plus`

Extractors are left untouched (except removing header) to avoid unnecessary merge conflicts

1 files changed, 17 insertions, 20 deletions

diff --git a/yt_dlp/extractor/common.py b/yt_dlp/extractor/common.py
index 8da21a3dc..ef22c7876 100644
--- a/yt_dlp/extractor/common.py
+++ b/yt_dlp/extractor/common.py
@@ -1,6 +1,3 @@
-# coding: utf-8
-from __future__ import unicode_literals
-
 import base64
 import collections
 import xml.etree.ElementTree
@@ -92,7 +89,7 @@ from ..utils import (
 )
 
 
-class InfoExtractor(object):
+class InfoExtractor:
     """Information Extractor class.
 
     Information extractors are the classes that, given a URL, extract
@@ -628,7 +625,7 @@ class InfoExtractor(object):
             if country:
                 self._x_forwarded_for_ip = GeoUtils.random_ipv4(country)
                 self._downloader.write_debug(
-                    'Using fake IP %s (%s) as X-Forwarded-For' % (self._x_forwarded_for_ip, country.upper()))
+                    f'Using fake IP {self._x_forwarded_for_ip} ({country.upper()}) as X-Forwarded-For')
 
     def extract(self, url):
         """Extracts URL information and returns it in list of dicts."""
@@ -741,9 +738,9 @@ class InfoExtractor(object):
             self.report_download_webpage(video_id)
         elif note is not False:
             if video_id is None:
-                self.to_screen('%s' % (note,))
+                self.to_screen(str(note))
             else:
-                self.to_screen('%s: %s' % (video_id, note))
+                self.to_screen(f'{video_id}: {note}')
 
         # Some sites check X-Forwarded-For HTTP header in order to figure out
         # the origin of the client behind proxy. This allows bypassing geo
@@ -779,7 +776,7 @@ class InfoExtractor(object):
             if errnote is None:
                 errnote = 'Unable to download webpage'
 
-            errmsg = '%s: %s' % (errnote, error_to_compat_str(err))
+            errmsg = f'{errnote}: {error_to_compat_str(err)}'
             if fatal:
                 raise ExtractorError(errmsg, cause=err)
             else:
@@ -860,7 +857,7 @@ class InfoExtractor(object):
             dump = base64.b64encode(webpage_bytes).decode('ascii')
             self._downloader.to_screen(dump)
         if self.get_param('write_pages', False):
-            basen = '%s_%s' % (video_id, urlh.geturl())
+            basen = f'{video_id}_{urlh.geturl()}'
             trim_length = self.get_param('trim_file_name') or 240
             if len(basen) > trim_length:
                 h = '___' + hashlib.md5(basen.encode('utf-8')).hexdigest()
@@ -1098,10 +1095,10 @@ class InfoExtractor(object):
 
     def to_screen(self, msg, *args, **kwargs):
         """Print msg to screen, prefixing it with '[ie_name]'"""
-        self._downloader.to_screen('[%s] %s' % (self.IE_NAME, msg), *args, **kwargs)
+        self._downloader.to_screen(f'[{self.IE_NAME}] {msg}', *args, **kwargs)
 
     def write_debug(self, msg, *args, **kwargs):
-        self._downloader.write_debug('[%s] %s' % (self.IE_NAME, msg), *args, **kwargs)
+        self._downloader.write_debug(f'[{self.IE_NAME}] {msg}', *args, **kwargs)
 
     def get_param(self, name, default=None, *args, **kwargs):
         if self._downloader:
@@ -1138,7 +1135,7 @@ class InfoExtractor(object):
             method = 'any' if self.supports_login() else 'cookies'
         if method is not None:
             assert method in self._LOGIN_HINTS, 'Invalid login method'
-            msg = '%s. %s' % (msg, self._LOGIN_HINTS[method])
+            msg = f'{msg}. {self._LOGIN_HINTS[method]}'
         raise ExtractorError(msg, expected=True)
 
     def raise_geo_restricted(
@@ -1257,7 +1254,7 @@ class InfoExtractor(object):
                 else:
                     raise netrc.NetrcParseError(
                         'No authenticators for %s' % netrc_machine)
-            except (IOError, netrc.NetrcParseError) as err:
+            except (OSError, netrc.NetrcParseError) as err:
                 self.report_warning(
                     'parsing .netrc: %s' % error_to_compat_str(err))
 
@@ -3333,7 +3330,7 @@ class InfoExtractor(object):
                             http_f = f.copy()
                             del http_f['manifest_url']
                             http_url = re.sub(
-                                REPL_REGEX, protocol + r'://%s/\g<1>%s\3' % (http_host, qualities[i]), f['url'])
+                                REPL_REGEX, protocol + fr'://{http_host}/\g<1>{qualities[i]}\3', f['url'])
                             http_f.update({
                                 'format_id': http_f['format_id'].replace('hls-', protocol + '-'),
                                 'url': http_url,
@@ -3354,7 +3351,7 @@ class InfoExtractor(object):
         formats = []
 
         def manifest_url(manifest):
-            m_url = '%s/%s' % (http_base_url, manifest)
+            m_url = f'{http_base_url}/{manifest}'
             if query:
                 m_url += '?%s' % query
             return m_url
@@ -3391,7 +3388,7 @@ class InfoExtractor(object):
             for protocol in ('rtmp', 'rtsp'):
                 if protocol not in skip_protocols:
                     formats.append({
-                        'url': '%s:%s' % (protocol, url_base),
+                        'url': f'{protocol}:{url_base}',
                         'format_id': protocol,
                         'protocol': protocol,
                     })
@@ -3557,7 +3554,7 @@ class InfoExtractor(object):
     def _int(self, v, name, fatal=False, **kwargs):
         res = int_or_none(v, **kwargs)
         if res is None:
-            msg = 'Failed to extract %s: Could not parse value %r' % (name, v)
+            msg = f'Failed to extract {name}: Could not parse value {v!r}'
             if fatal:
                 raise ExtractorError(msg)
             else:
@@ -3567,7 +3564,7 @@ class InfoExtractor(object):
     def _float(self, v, name, fatal=False, **kwargs):
         res = float_or_none(v, **kwargs)
         if res is None:
-            msg = 'Failed to extract %s: Could not parse value %r' % (name, v)
+            msg = f'Failed to extract {name}: Could not parse value {v!r}'
             if fatal:
                 raise ExtractorError(msg)
             else:
@@ -3685,7 +3682,7 @@ class InfoExtractor(object):
     def _merge_subtitle_items(subtitle_list1, subtitle_list2):
         """ Merge subtitle items for one language. Items with duplicated URLs/data
         will be dropped. """
-        list1_data = set((item.get('url'), item.get('data')) for item in subtitle_list1)
+        list1_data = {(item.get('url'), item.get('data')) for item in subtitle_list1}
         ret = list(subtitle_list1)
         ret.extend(item for item in subtitle_list2 if (item.get('url'), item.get('data')) not in list1_data)
         return ret
@@ -3798,7 +3795,7 @@ class SearchInfoExtractor(InfoExtractor):
         else:
             n = int(prefix)
             if n <= 0:
-                raise ExtractorError('invalid download number %s for query "%s"' % (n, query))
+                raise ExtractorError(f'invalid download number {n} for query "{query}"')
             elif n > self._MAX_RESULTS:
                 self.report_warning('%s returns max %i results (you requested %i)' % (self._SEARCH_KEY, self._MAX_RESULTS, n))
                 n = self._MAX_RESULTS