code: def header_decode(s):
      
      s = s.replace('_', ' ')
      return re.sub(r'=[a-fA-F0-9]{2}', _unquote_match, s, re.ASCII)
docs: Decode a string encoded with RFC 2045 MIME header `Q' encoding.
  
      This function does not parse a full MIME header value encoded with
      quoted-printable (like =?iso-8895-1?q?Hello_World?=) -- please use
      the high level email.header class for that functionality.