[utils] Add filter_dict

yt_dlp/extractor/rai.py

@@ -11,6 +11,7 @@ from ..compat import (
 from ..utils import (
     determine_ext,
     ExtractorError,
+    filter_dict,
     find_xpath_attr,
     fix_xml_ampersands,
     GeoRestrictedError,
@@ -110,11 +111,11 @@ class RaiBaseIE(InfoExtractor):
         if not audio_only:
             formats.extend(self._create_http_urls(relinker_url, formats))
 
-        return dict((k, v) for k, v in {
+        return filter_dict({
             'is_live': is_live,
             'duration': duration,
             'formats': formats,
-        }.items() if v is not None)
+        })
 
     def _create_http_urls(self, relinker_url, fmts):
         _RELINKER_REG = r'https?://(?P<host>[^/]+?)/(?:i/)?(?P<extra>[^/]+?)/(?P<path>.+?)/(?P<id>\d+)(?:_(?P<quality>[\d\,]+))?(?:\.mp4|/playlist\.m3u8).+?'