def METHOD_NAME(all_metrics, matchers):
  """Verified that every matcher matches a metric result in all_metrics."""
  errors = []
  matched_metrics = []
  for matcher in matchers:
    matched_metrics = [mr for mr in all_metrics if matcher.matches(mr)]
    if not matched_metrics:
      errors.append(
          'Unable to match metrics for matcher %s' %
          (string_description.tostring(matcher)))
  if errors:
    errors.append(
        '\nActual MetricResults:\n' + '\n'.join([str(mr)
                                                 for mr in all_metrics]))
  return ''.join(errors)