@classmethod
def encode_header_items(cls, header_items):
    """
        Prepare the sequence of name, value tuples into a form suitable for
        transmitting on the wire for HTTP.
        """
    for k, v in header_items:
        if not isinstance(v, str) and not isinstance(v, bytes):
            v = str(v)
        yield tuple(map(cls.encode_header_item, (k, v)))
