code: def identity_simplify(expr, op_name, identity_val):
      if expr[0] != op_name:
          return None
      if len(expr) == 2:
          return expr[1]
      new_args = []
      did_something = False
      for i in expr[1:]:
          if i[0] != identity_val:
              new_args.append(i)
          else:
              did_something = True
      if did_something:
          if len(new_args) > 1:
              return (op_name,) + tuple(new_args)
          else:
              return new_args[0]
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  import numpy
  import tensorflow
label_desc: Use image node_id 17 for calling a global function with example usage: identity_simplify(expr, op_name, identity_val) and returns: None, expr, unknown, new_args