    def set_activation(self, activation):
        """Sets the activation function for this layer.

        Arguments:
            activation: (str) The activation function to be used.

        Returns: None.
        """
        if self.variables_constructed:
            raise RuntimeError("Variables already constructed.")
        self.activation = activation
Sets the activation function for this layer.

Arguments:
activation: (str) The activation function to be used.

Returns: None.
mbpo/models/fc.py