(func: str, backend: str, default: Any = None)
Try and import ``{backend}.{func}``.
    If library is installed and func is found, return the func;
    otherwise if default is provided, return default;
    otherwise raise an error.
Try and import ``{backend}.{func}``.
    If library is installed and func is found, return the func;
    otherwise if default is provided, return default;
    otherwise raise an error.
Try and import { backend } . { func } . If library is installed and func is found return the func ; otherwise if default is provided return default ; otherwise raise an error .
def _import_func(func: str, backend: str, default: Any = None) -> Any:
    """Try and import ``{backend}.{func}``.
    If library is installed and func is found, return the func;
    otherwise if default is provided, return default;
    otherwise raise an error.
    """
    try:
        lib = importlib.import_module(_aliases.get(backend, backend))
        return getattr(lib, func) if default is None else getattr(lib, func, default)
    except AttributeError:
        error_msg = (
            "{} doesn't seem to provide the function {} - see "
            "https://optimized-einsum.readthedocs.io/en/latest/backends.html "
            "for details on which functions are required for which contractions."
        )
        raise AttributeError(error_msg.format(backend, func))
def _import_func ( func : str , backend : str , default : Any = None ) -> Any : try : lib = importlib . import_module ( _aliases . get ( backend , backend ) ) return getattr ( lib , func ) if default is None else getattr ( lib , func , default ) except AttributeError : error_msg = ( "{} doesn't seem to provide the function {} - see " "https://optimized-einsum.readthedocs.io/en/latest/backends.html " "for details on which functions are required for which contractions." ) raise AttributeError ( error_msg . format ( backend , func ) )