code: def _make_urp_hash(username, realm, passwd):
      
      if realm is None:
          realm = b""
      return _h_value(b":".join((username, realm, passwd)))
docs: Compute MD5 sum of username:realm:password.
  
      :Parameters:
          - `username`: a username.
          - `realm`: a realm.
          - `passwd`: a password.
      :Types:
          - `username`: `bytes`
          - `realm`: `bytes`
          - `passwd`: `bytes`
  
      :return: the MD5 sum of the parameters joined with ':'.
      :returntype: `bytes`