def select_from_backends(backends):
                """
                Selects from presented backends and returns the first working
                """
                lib = None
                for backend in backends:
                    lib = select_known_backend(backend)
                    if lib is not None:
                        break
                else:
                    backend = ''
                return lib, backend

                Selects from presented backends and returns the first working
                
numba/np/ufunc/parallel.py