docstr: Create an async socket from an existing Socket
docstr_tok: ["Create","an","async","socket","from","an","existing","Socket"]
code: def from_socket(cls, socket, io_loop=None):
      """Create an async socket from an existing Socket"""
      return cls(_from_socket=socket, io_loop=io_loop)
  
imports: from collections import namedtuple, deque
  from itertools import chain
  from zmq import EVENTS, POLLOUT, POLLIN
  import zmq
label_desc: Use image node_id 2 for calling the _AsyncSocket obj's underlying member method code with example usage: obj.from_socket(cls, socket, io_loop) and returns: cls