code: def create(self, instance, parameters, existing=True):
          
          return self.service_instance.create(instance, parameters, existing)
docs: Create an instance
          
          Args:
              instance (AtlasServiceInstance.Instance): Existing or New instance
              parameters (dict): Parameters for the instance
              
          Keyword Arguments:
              existing (bool): True (use an existing cluster), False (create a new cluster)
          
          Returns:
              ProvisionedServiceSpec: Status