code: def softplus(x):
      """Softplus activation function, `softplus(x) = log(exp(x) + 1)`.
  
      Example Usage:
  
      >>> a = tf.constant([-20, -1.0, 0.0, 1.0, 20], dtype = tf.float32)
      >>> b = tf.keras.activations.softplus(a)
      >>> b.numpy()
      array([2.0611537e-09, 3.1326166e-01, 6.9314718e-01, 1.3132616e+00,
               2.0000000e+01], dtype=float32)
  
      Args:
          x: Input tensor.
  
      Returns:
          The softplus activation: `log(exp(x) + 1)`.
      """
      return math_ops.softplus(x)
  
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 4 for calling a global function with example usage: softplus(x) and returns: math_ops