code: def unify(a, b):
      U = unify_walk(a, b, Unification())
      if not U:
          return None, False
      else:
          return unify_merge(a, b, U), U
  
imports: from __future__ import absolute_import, print_function, division
  from copy import copy
  from functools import partial
  from theano.gof.utils import ANY_TYPE, comm_guard, FALL_THROUGH, iteritems
label_desc: Use image node_id 27 for calling a global function with example usage: unify(a, b) and returns: None,  False, unify_merge,  U