'send a Python unicode string as a message with an encoding
0MQ communicates with raw bytes, so you must encode/decode
text (unicode on py2, str on py3) around 0MQ.
Parameters
u : Python unicode string (unicode on py2, str on py3)
The unicode string to send.
flags : int, optional
Any valid send flag.
encoding : str [default: \'utf-8\']
The encoding to be used'

def send_string(self, u, flags=0, copy=True, encoding='utf-8'):

    if (not isinstance(u, basestring)):
        raise TypeError('unicode/str    objects    only')
    return self.send(u.encode(encoding), flags=flags, copy=copy)
