Code checker

I would add a function that checks that if the code is out of the valid range, then False is returned:
`
def is_bad_code(code):
return 100 < code or code >= 526
`

No file or test is named. Start by locating the code that handles HTTP status codes and determine where the requested is_bad_code function belongs; confirm the valid range and verify that codes below 100 or at least 526 return False, while in-range codes are accepted.

Written by the indexing model from the issue text.