examples/demo_custom_layer_backend_agnostic.py/MyDense/build
class MyDense:    def build(self, input_shape):
        input_dim = input_shape[-1]
        self.w = self.add_weight(
            shape=(input_dim, self.units),
            initializer=initializers.GlorotNormal(),
            name="kernel",
            trainable=True,
        )

        self.b = self.add_weight(
            shape=(self.units,),
            initializer=initializers.Zeros(),
            name="bias",
            trainable=True,
        )