Add brief docstring for the method `DecortController.account_resource_groups`

module_utils/decort_utils.py

@@ -2207,6 +2207,11 @@ class DecortController(object):
             vins_id: None | int = None,
             vm_id: None | int = None,
             ) -> list[dict]:
+        """
+        Implementation of functionality of the API method
+        `/cloudapi/account/listRG`.
+        """
+
         if rg_status and not rg_status in self.RESOURCE_GROUP_STATUSES:
             self.result['msg'] = (
                 f'{rg_status} is not valid RG status for filtering'