def requestor(address,callback,message_type):
return Requestor(address,callback,message_type)<EOL>
Creates a requestor binding to the given address send requests.
The callback is invoked for every reply received.

    Args:
        - address: the address to bind the REQ socket to.
        - callback: the callback to invoke for every message. Must accept 2 variables - message and the requestor
        - message_type: the type of message to receive