def METHOD_NAME(context: Context, parameter: str, value: str) -> None:
    """Check that all sources have a parameter with the specified value."""
    for report in context.get("report/")["reports"]:
        for subject in report["subjects"].values():
            for metric in subject["metrics"].values():
                for source in metric["sources"].values():
                    assert_not_equal(value, source["parameters"].get(parameter))