axon_population.valid_mask_labels axon_population.valid_mask_labels(mask_labels: None | Iterable[str] | str = None) → list[str] Keep only mask labels that exist in the population. Parameters: mask_labels (None | Iterable[str] | str, optional) – Mask label specification to validate. Returns: Existing mask labels extracted from mask_labels. Return type: list[str]