The path to a builtin asset in the ./data folder on this machine.

Parameters:asset_filename (str) – The filename (with extension) of a file builtin to Menpo. The full set of allowed names is given by ls_builtin_assets()
Returns:data_path (pathlib.Path) – The path to a given asset in the ./data folder
Raises:ValueError – If the asset_filename doesn’t exist in the data folder.