def add_metric(self, labels, value, created=None, timestamp=None):
self.samples.append(Sample(self.name + '<STR_LIT>', dict(zip(self._labelnames, labels)), value, timestamp))<EOL>if created is not None:<EOL><INDENT>self.samples.append(Sample(self.name + '<STR_LIT>', dict(zip(self._labelnames, labels)), created, timestamp))<EOL><DEDENT>
Add a metric to the metric family.

        Args:
          labels: A list of label values
          value: The value of the metric
          created: Optional unix timestamp the child was created at.