code: def _log_deprecation(self, deprecation_key):
          
          if not self._deprecations[deprecation_key][0]:
              self.log.warning(self._deprecations[deprecation_key][1])
              self._deprecations[deprecation_key][0] = True
docs: Logs a deprecation notice at most once per AgentCheck instance, for the pre-defined `deprecation_key`