Don't compare bytes and str in putheader()
MODIFY
src/urllib3/connection.py
src/urllib3/connection.py
@@ -184,7 +184,7 @@ class HTTPConnection(_HTTPConnection):
def putheader(self, header, *values):
""""""
- if SKIP_HEADER not in values:
+ if not any(isinstance(v, str) and v == SKIP_HEADER for v in values):
super().putheader(header, *values)
elif to_str(header.lower()) not in SKIPPABLE_HEADERS:
raise ValueError(

Don't compare bytes and str in putheader()