keras/src/layers/preprocessing/feature_space.py/FeatureSpace/_check_if_adapted
class FeatureSpace:    def _check_if_adapted(self):
        if not self._is_adapted:
            if not self._list_adaptable_preprocessors():
                self._is_adapted = True
            else:
                raise ValueError(
                    "You need to call `.adapt(dataset)` on the FeatureSpace "
                    "before you can start using it."
                )