code: def get(identifier):
      """Returns function.
  
      Args:
          identifier: Function or string
  
      Returns:
          Function corresponding to the input string or input function.
  
      For example:
  
      >>> tf.keras.activations.get('softmax')
       <function softmax at 0x1222a3d90>
      >>> tf.keras.activations.get(tf.keras.activations.softmax)
       <function softmax at 0x1222a3d90>
      >>> tf.keras.activations.get(None)
       <function linear at 0x1239596a8>
      >>> tf.keras.activations.get(abs)
       <built-in function abs>
      >>> tf.keras.activations.get('abcd')
      Traceback (most recent call last):
      ...
      ValueError: Unknown activation function:abcd
  
      Raises:
          ValueError: Input is an unknown function or string, i.e., the input does
          not denote any defined function.
      """
      if identifier is None:
          return linear
      if isinstance(identifier, str):
          identifier = str(identifier)
          return deserialize(identifier)
      elif isinstance(identifier, dict):
          return deserialize(identifier)
      elif callable(identifier):
          return identifier
      else:
          raise TypeError(
              "Could not interpret activation function identifier: {}".format(
                  identifier
              )
          )
  
imports: from tensorflow.python.keras import backend
  from tensorflow.python.keras.layers import advanced_activations
  from tensorflow.python.keras.utils.generic_utils import deserialize_keras_object
  from tensorflow.python.keras.utils.generic_utils import serialize_keras_object
  from tensorflow.python.ops import math_ops
  from tensorflow.python.ops import nn
  from tensorflow.python.util import dispatch
label_desc: Use image node_id 16 for calling a global function with example usage: get(identifier) and returns: linear, deserialize, deserialize, identifier