docs: def poll(self, endpoint, pFormat=PrometheusFormat.PROTOBUF, headers=None):
          """
          Polls the metrics from the prometheus metrics endpoint provided.
          Defaults to the protobuf format, but can use the formats specified by
          the PrometheusFormat class.
          Custom headers can be added to the default headers.
  
          Returns a valid requests.Response, raise requests.HTTPError if the status code of the requests.Response
          isn't valid - see response.raise_for_status()
  
          The caller needs to close the requests.Response
  
          :param endpoint: string url endpoint
          :param pFormat: the preferred format defined in PrometheusFormat
          :param headers: extra headers
          :return: requests.Response
          """
          if headers is None:
              headers = {}
          if 'accept-encoding' not in headers:
              headers['accept-encoding'] = 'gzip'
          if pFormat == PrometheusFormat.PROTOBUF:
              headers['accept'] = (
                  'application/vnd.google.protobuf; ' 'proto=io.prometheus.client.MetricFamily; ' 'encoding=delimited'
              )
          headers.update(self.extra_headers)
          cert = None
          if isinstance(self.ssl_cert, string_types):
              cert = self.ssl_cert
              if isinstance(self.ssl_private_key, string_types):
                  cert = (self.ssl_cert, self.ssl_private_key)
          verify = True
          if isinstance(self.ssl_ca_cert, string_types):
              verify = self.ssl_ca_cert
          elif self.ssl_ca_cert is False:
              disable_warnings(InsecureRequestWarning)
              verify = False
          try:
              response = requests.get(
                  endpoint, headers=headers, stream=False, timeout=self.prometheus_timeout, cert=cert, verify=verify
              )
          except requests.exceptions.SSLError:
              self.log.error("Invalid SSL settings for requesting {} endpoint".format(endpoint))
              raise
          except IOError:
              if self.health_service_check:
                  self._submit_service_check(
                      "{}{}".format(self.NAMESPACE, ".prometheus.health"),
                      AgentCheck.CRITICAL,
                      tags=["endpoint:" + endpoint],
                  )
              raise
          try:
              response.raise_for_status()
              if self.health_service_check:
                  self._submit_service_check(
                      "{}{}".format(self.NAMESPACE, ".prometheus.health"), AgentCheck.OK, tags=["endpoint:" + endpoint]
                  )
              return response
          except requests.HTTPError:
              response.close()
              if self.health_service_check:
                  self._submit_service_check(
                      "{}{}".format(self.NAMESPACE, ".prometheus.health"),
                      AgentCheck.CRITICAL,
                      tags=["endpoint:" + endpoint],
                  )
              raise