import tensorflow as tf

        with tf.variable_scope(scope):
            if self._max_diffusion_step == 0:
                pass
            else:
                for support in self._supports:
                    x1 = tf.sparse_tensor_dense_matmul(support, x0)
                    x = self._concat(x, x1)

                    for _ in range(2, self._max_diffusion_step + 1):
                        x2 = 2 * tf.sparse_tensor_dense_matmul(support, x1) - x0
