code: def is_placeholder(n):
      return (
          (hasattr(n, "_op") and n._op.type == "Placeholder")
          or "_input" in str(n)
          or "input" in str(n)
      )
  
imports: import json
  import os
  from collections import OrderedDict
  import numpy
  import tensorflow
  import tensorflow.keras.backend
  from tensorflow.keras import Sequential
  from tensorflow.keras.models import Model
label_desc: Use image node_id 1 for calling a global function with example usage: is_placeholder(n) and returns: unknown