keras/src/layers/attention/additive_attention.py/AdditiveAttention/build
class AdditiveAttention:    def build(self, input_shape):
        self._validate_inputs(input_shape)
        dim = input_shape[0][-1]
        self.scale = None
        if self.use_scale:
            self.scale = self.add_weight(
                name="scale",
                shape=[dim],
                initializer="glorot_uniform",
                dtype=self.dtype,
                trainable=True,
            )
        self.built = True