def METHOD_NAME(
    self, name, input_transform, outcome_transform
) -> Optional[CustomMean]:
    """Builds the mean module for the output specified by name."""
    mean_module = self._get_module(self.mean_modules, name)
    if mean_module is not None:
        fixed_model = False if name in self.trainable_mean_keys else True
        mean_module = CustomMean(
            mean_module, input_transform, outcome_transform, fixed_model=fixed_model
        )
    return mean_module