code: def _merge_masks(x, y):
      if x is None:
          return y
      if y is None:
          return x
      return math_ops.logical_and(x, y)
  
imports: from tensorflow.python.framework import dtypes
  from tensorflow.python.framework import tensor_conversion
  from tensorflow.python.framework import tensor_shape
  from tensorflow.python.keras import backend
  from tensorflow.python.keras.engine.base_layer import Layer
  from tensorflow.python.keras.utils import control_flow_util
  from tensorflow.python.ops import array_ops
  from tensorflow.python.ops import init_ops
  from tensorflow.python.ops import math_ops
  from tensorflow.python.ops import nn
label_desc: Use image node_id 2 for calling a global function with example usage: _merge_masks(x, y) and returns: math_ops, y, x