ValueError:未知层: RBFLayer

import tensorflow as tf

class RBFLayer(tf.keras.layers.Layer):
    def __init__(self, units):
        super(RBFLayer, self).__init__()
        self.units = units

    def build(self, input_shape):
        self.centers = self.add_weight(
            name='centers',
            shape=(self.units, input_shape[1]),
            initializer='random_normal',
            trainable=True
        )
        self.sigma = self.add_weight(
            name='sigma',
            shape=(self.units,),
            initializer='ones',
            trainable=True
        )

    def call(self, inputs):
        inputs = tf.expand_dims(inputs, 1)
        diff = inputs - self.centers
        squared_diff = tf.square(diff)
        summed = tf.reduce_sum(squared_diff, axis=-1)
        return tf.exp(-summed / (2*self.sigma**2))