code: def _safe_add(x, y):
      """Adds x and y but if y is None, simply returns x."""
      return x if y is None else tf.add(x, y)
  
file_path: privacy/tensorflow_privacy/privacy/dp_query/dp_query.py
imports: import abc
  import collections
  import tensorflow
label_desc: Use image node_id 2 for calling a global function with example usage: _safe_add(x, y) and returns: unknown