docs: def _match_mask(mask, ctype):
      """
      Determine if a content type mask matches a given content type.
  
      :param mask: The content type mask, taken from the Accept
                   header.
      :param ctype: The content type to match to the mask.
      """
  
      # Handle the simple cases first
      if '*' not in mask:
          return ctype == mask
      elif mask == '*/*':
          return True
      elif not mask.endswith('/*'):
          return False
  
      mask_major = mask[:-2]
      ctype_major = ctype.split('/', 1)[0]
      return ctype_major == mask_major