code: def call(self, action, payload):
          
          if self.api_key:
              payload['Bugzilla_api_key'] = self.api_key
          d = self.proxy.callRemote(action, payload)
          d.addErrback(self._parse_errback)
          return d
docs: Make an XML-RPC call to the server. This method will automatically
          authenticate the call with self.api_key, if that is set.
  
          returns: deferred that when fired returns a dict with data from this
                   XML-RPC call.