from abc import ABCMeta from typing import ( Callable, Container, Generic, Iterable, Iterator, Mapping, Tuple, TypeVar, Union, ) KT = TypeVar("KT") # Identifier. RT = TypeVar("RT") # Requirement. CT = TypeVar("CT") # Candidate. _T = TypeVar("_T") Matches = Union[Iterable[CT], Callable[[], Iterable[CT]]] class IteratorMapping(Mapping[KT, _T], metaclass=ABCMeta): pass class IterableView(Container[CT], Iterable[CT], metaclass=ABCMeta): pass class DirectedGraph(Generic[KT]): def __iter__(self) -> Iterator[KT]: ... def __len__(self) -> int: ... def __contains__(self, key: KT) -> bool: ... def copy(self) -> "DirectedGraph[KT]": ... def add(self, key: KT) -> None: ... def remove(self, key: KT) -> None: ... def connected(self, f: KT, t: KT) -> bool: ... def connect(self, f: KT, t: KT) -> None: ... def iter_edges(self) -> Iterable[Tuple[KT, KT]]: ... def iter_children(self, key: KT) -> Iterable[KT]: ... def iter_parents(self, key: KT) -> Iterable[KT]: ... def build_iter_view(matches: Matches) -> IterableView[CT]: ...