Method _assert_state

src/_pytest/capture.py:383–388

(self, op: str, states: Tuple[str, ...])

        )

    def _assert_state(self, op: str, states: Tuple[str, ...]) -> None:
        assert (
            self._state in states
        ), "cannot {} in state {!r}: expected one of {}".format(
            op, self._state, ", ".join(states)
        )

    def start(self) -> None:
        """Start capturing on targetfd using memorized tmpfile."""