in glean_parser/metrics.py [0:0]
def validate_extra_keys(extra_keys: Dict[str, str], config: Dict[str, Any]) -> None:
if not config.get("allow_reserved") and any(
k.startswith("glean.") for k in extra_keys.keys()
):
raise ValueError(
"Extra keys beginning with 'glean.' are reserved for "
"Glean internal use."
)