keras/src/layers/reshaping/zero_padding1d.py/ZeroPadding1D/compute_output_shape
class ZeroPadding1D:    def compute_output_shape(self, input_shape):
        output_shape = list(input_shape)
        if output_shape[1] is not None:
            output_shape[1] += self.padding[0] + self.padding[1]
        return tuple(output_shape)