<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def check_metric(self, metric):
 """Check that the metric is supported by the KNNIndex instance."""

        if metric not in self.VALID_METRICS:
            raise ValueError(
                f"`{self.__class__.__name__}` does not support the `{metric}` "
                f"metric. Please choose one of the supported metrics: "
                f"{', '.join(self.VALID_METRICS)}."
            )