Method run

contextvars/__init__.py:30–41

(self, callable, *args, **kwargs)

        self._prev_context = None

    def run(self, callable, *args, **kwargs):
        if self._prev_context is not None:
            raise RuntimeError(
                'cannot enter context: {} is already entered'.format(self))

        self._prev_context = _get_context()
        try:
            _set_context(self)
            return callable(*args, **kwargs)
        finally:
            _set_context(self._prev_context)
            self._prev_context = None

    def copy(self):
        new = Context()