def warn(self, fmt, **args):
    from _pytest.warnings import _issue_config_warning
    from _pytest.warning_types import PytestWarning
    _issue_config_warning(PytestWarning((fmt.format(**args) if args else fmt)), self._config)
def warn(self, fmt, **args):
    from _pytest.warnings import _issue_config_warning
    from _pytest.warning_types import PytestWarning
    _issue_config_warning(PytestWarning((fmt.format(**args) if args else fmt)), self._config)