docs: def register_binary_type(content_type, dumper, loader):
      """
      Register handling for a binary content type.
  
      :param str content_type: content type to register the hooks for
      :param dumper: called to decode bytes into a dictionary.
          Calling convention: ``dumper(obj_dict) -> bytes``.
      :param loader: called to encode a dictionary into a byte string.
          Calling convention: ``loader(obj_bytes) -> dict``
  
      """
      content_type = headers.parse_content_type(content_type)
      content_type.parameters.clear()
      key = str(content_type)
      _content_types[key] = content_type
  
      handler = _content_handlers.setdefault(key, _ContentHandler(key))
      handler.dict_to_bytes = dumper
      handler.bytes_to_dict = loader