[extractor] Framework for embed detection (#4307)

devscripts/lazy_load_template.py

@@ -9,11 +9,13 @@ from ..utils import (
     write_string,
 )
 
+# These bloat the lazy_extractors, so allow them to passthrough silently
+ALLOWED_CLASSMETHODS = {'get_testcases', 'extract_from_webpage'}
+
 
 class LazyLoadMetaClass(type):
     def __getattr__(cls, name):
-        # "_TESTS" bloat the lazy_extractors
-        if '_real_class' not in cls.__dict__ and name != 'get_testcases':
+        if '_real_class' not in cls.__dict__ and name not in ALLOWED_CLASSMETHODS:
             write_string(
                 'WARNING: Falling back to normal extractor since lazy extractor '
                 f'{cls.__name__} does not have attribute {name}{bug_reports_message()}\n')