rpc_send() error when using latest sysrepo

[pepa-cz]

Using the latest sysrepo version I started getting the following errors. It is caused by change of sysrepo API of functions sr_rpc_send*, where return value can be NULL . This is typically the case of rpc/action not returning any output. However, now is NULL correct value meaning that no output node is generated:

[out] output SR data with the output data tree, NULL if no output nodes were generated.

Error:

 self = <sysrepo.session.SysrepoSession object at 0x7767f34fb780>
 rpc_input = <[AttributeError("cdata 'void *' has no attribute 'schema'") raised in repr()] DContainer object at 0x7767f3022b70>
 timeout_ms = 0

     def rpc_send_ly(
         self, rpc_input: libyang.DNode, timeout_ms: int = 0
     ) -> libyang.DNode:
         """
         Send an RPC/action and wait for the result.

         RPC/action must be valid in (is validated against) the operational datastore
         context.

         :arg rpc_input:
             The RPC/action input tree. It is *NOT* spent and must be freed by the
             caller.
         :arg timeout_ms:
             RPC/action callback timeout in milliseconds. If 0, default is used.

         :returns:
             The RPC/action output tree. Allocated dynamically and must be freed by the
             caller.
         :raises SysrepoError:
             If the RPC/action callback failed.
         """
         if not isinstance(rpc_input, libyang.DNode):
             raise TypeError("rpc_input must be a libyang.DNode")
         # libyang and sysrepo bindings are different, casting is required
         in_dnode = ffi.cast("struct lyd_node *", rpc_input.cdata)
         sr_data_p = ffi.new("sr_data_t **")
         check_call(lib.sr_rpc_send_tree, self.cdata, in_dnode, timeout_ms, sr_data_p)
         if not sr_data_p[0]:
 >           raise SysrepoInternalError("sr_rpc_send_tree returned NULL")
 E           sysrepo.errors.SysrepoInternalError: sr_rpc_send_tree returned NULL: Internal error

 /lib/python3.11/site-packages/sysrepo/session.py:1473: SysrepoInternalError