code: def swish(x, name='swish'):
      
      with tf.name_scope(name):
          x = tf.nn.sigmoid(x) * x
      return x
docs: Swish function.
  
       See `Swish: a Self-Gated Activation Function <https://arxiv.org/abs/1710.05941>`__.
  
      Parameters
      ----------
      x : Tensor
          input.
      name: str
          function name (optional).
  
      Returns
      -------
      Tensor
          A ``Tensor`` in the same type as ``x``.