code: def unify_merge(l1, l2, U):
      return [unify_merge(x1, x2, U) for x1, x2 in zip(l1, l2)]
  
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 21 for calling a global function with example usage: unify_merge(l1, l2, U) and returns: unknown