resource_dfn_clone: Fix exception if curl option was set

Author: rp-

CHANGELOG.md

@@ -15,6 +15,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ### Fixed
 
 - Correctly pass parameters in error_report_delete
+- resource_dfn_clone: Fix exception if curl option was set
 
 ## [1.25.2] - 2025-04-08
 

linstor/linstorapi.py

@@ -2007,7 +2007,7 @@ def resource_dfn_clone(
         :param optional[list[str]] layer_list: Set of layer names to use.
         :param optional[str] resource_group: Resource group the cloned resource should use.
         :return:
-        :rtype: CloneStarted
+        :rtype: optional[CloneStarted]
         """
         self._require_version("1.10.0", msg="Resource definition clone API not supported by server")
 
@@ -2036,12 +2036,13 @@ def resource_dfn_clone(
             self._require_version("1.23.0", msg="Clone resource-group parameter not supported")
             body["resource_group"] = resource_group
 
-        return self._rest_request(
+        result = self._rest_request(
             apiconsts.API_CLONE_RSCDFN,
             "POST", _pquote("/v1/resource-definitions/{}/clone", src_name),
             body,
             raise_error=True
-        )[0]
+        )
+        return result[0] if result else None
 
     def resource_dfn_clone_status(self, src_name, clone_name):
         """