    def set_input_dim(self, input_dim):
        """Sets the dimension of the input.

        Arguments:
            input_dim: (int) The dimension of the input.

        Returns: None
        """
        if self.variables_constructed:
            raise RuntimeError("Variables already constructed.")
        self.input_dim = input_dim
Sets the dimension of the input.

Arguments:
input_dim: (int) The dimension of the input.

Returns: None
mbpo/models/fc.py