code: func (c *CloudWatch) ListMetrics(input *ListMetricsInput) (*ListMetricsOutput, error) {
  	req, out := c.ListMetricsRequest(input)
  	return out, req.Send()
  }
docs: // ListMetrics API operation for Amazon CloudWatch.
  //
  // List the specified metrics. You can use the returned metrics with GetMetricData
  // or GetMetricStatistics to obtain statistical data.
  //
  // Up to 500 results are returned for any one call. To retrieve additional results,
  // use the returned token with subsequent calls.
  //
  // After you create a metric, allow up to fifteen minutes before the metric
  // appears. Statistics about the metric, however, are available sooner using
  // GetMetricData or GetMetricStatistics.
  //
  // Returns awserr.Error for service API and SDK errors. Use runtime type assertions
  // with awserr.Error's Code and Message methods to get detailed information about
  // the error.
  //
  // See the AWS API reference guide for Amazon CloudWatch's
  // API operation ListMetrics for usage and error information.
  //
  // Returned Error Codes:
  //   * ErrCodeInternalServiceFault "InternalServiceError"
  //   Request processing has failed due to some unknown error, exception, or failure.
  //
  //   * ErrCodeInvalidParameterValueException "InvalidParameterValue"
  //   The value of an input parameter is bad or out-of-range.
  //
  // See also, https://docs.aws.amazon.com/goto/WebAPI/monitoring-2010-08-01/ListMetrics