code: def __call__(self, u):
      return self.fn(*[unify_build(arg, u) for arg in self.args])
  
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 2 for calling the FVar obj's underlying member method code with example usage: obj.__call__(u) and returns: self