Refactor _get_color function to stop using private scanpy functions and to work with mudata

[grst]

See

scirpy/scirpy/pl/styling.py

Lines 123 to 164 in 8ad2e8b

	def _get_colors(
	params: DataHandler,
	obs_key: str,
	palette: Union[str, Sequence[str], Cycler, None] = None,
	) -> Optional[Dict[str, str]]:
	"""Return colors for a category stored in AnnData.
	If colors are not stored, new ones are assigned.
	Since we currently don't plot expression values, only keys from `obs`
	are supported, while in scanpy `values_to_plot` (used instead of `obs_key`)
	can be a key from either `obs` or `var`.
	TODO: This makes use of private scanpy functions. This is evil and
	should be changed in the future.
	"""
	# required to turn into categoricals
	params.data.strings_to_categoricals()
	# we can only get a palette for columns that are now categorical. Boolean/int/... won't work
	if isinstance(params.data, MuData):
	if obs_key in params.data.obs.columns:
	uns_lookup = params.data
	else:
	uns_lookup = params.adata
	else:
	uns_lookup = params.adata
	if uns_lookup.obs[obs_key].dtype.name == "category":
	values = uns_lookup.obs[obs_key].values
	categories = values.categories # type: ignore
	color_key = f"{obs_key}_colors"
	if palette is not None:
	_set_colors_for_categorical_obs(uns_lookup, obs_key, palette)
	elif color_key not in uns_lookup.uns or len(uns_lookup.uns[color_key]) < len(
	categories
	):
	# set a default palette in case that no colors or few colors are found
	_set_default_colors_for_categorical_obs(uns_lookup, obs_key)
	else:
	_validate_palette(uns_lookup, obs_key)
	return {cat: col for cat, col in zip(categories, uns_lookup.uns[color_key])}