code: def serve(server, host=None, port=None, profile=".bash_profile"):
      """begin serving RPC requests
  
      Args:
          server: name of RPC server  (i.e. 'ppserver')
          host: hostname on which a server should be launched
          port: port number (on host) that server will accept request at
          profile: file to configure the user's environment [default='.bash_profile']
      """
      if host is None:  # XXX: and...?
          profile = ""
      else:
          profile = "source %s; " % profile
      file = "~/bin/%s.py" % server  # XXX: _should_ be on the $PATH
      if port is None:
          port = randomport(host)
      command = "%s -p %s" % (file, port)
      rserver = execute(command, host, bg=True)
      response = rserver.response()
      pathos.logger().info("response = %r", response)
      if response in ["", None]:  # XXX: other responses allowed (?)
          pass
      else:  # XXX: not really error checking...
          pathos.logger().error("invalid response = %r", response)
      from time import sleep
  
      delay = 2.0
      sleep(delay)
      return rserver
  
file_path: pathos/pathos/core.py
imports: import os
  import string
  import re
  import pathos
label_desc: Use image node_id 11 for calling a global function with example usage: serve(server, host, port, profile) and returns: rserver