code: def register_linker(name, linker):
      """Add a `Linker` which can be referred to by `name` in `Mode`."""
      if name in predefined_linkers:
          raise ValueError("Linker name already taken: %s" % name)
      predefined_linkers[name] = linker
  
imports: from __future__ import absolute_import, print_function, division
  import logging
  import warnings
  import theano
  from theano import gof
  import theano.gof.vm
  from theano import config
  from six import string_types
  from theano.compile.function_module import Supervisor
label_desc: Use image node_id 1 for calling a global function with example usage: register_linker(name, linker) without return types