def generate_random_64bit_string():
return '<STR_LIT>'.format(random.getrandbits(<NUM_LIT:64>))<EOL>
Returns a 64 bit UTF-8 encoded string. In the interests of simplicity,
    this is always cast to a `str` instead of (in py2 land) a unicode string.
    Certain clients (I'm looking at you, Twisted) don't enjoy unicode headers.

    :returns: random 16-character string