code: def make_poll():
      os = platform.system()
      if os == "Linux":
          return LinuxProcPoll()
      elif os == "Darwin":
          return DarwinProcPoll()
      else:
          raise Exception(
              "Polling is not supported on "
              "your operating system (%s)" % os
          )
  
imports: import platform
  import select
label_desc: Use image node_id 1 for calling a global function with example usage: make_poll() and returns: LinuxProcPoll, DarwinProcPoll