diff --git a/src/ska_tango_base/subarray/subarray_device.py b/src/ska_tango_base/subarray/subarray_device.py
index d030a18523de479c2a4bdfe1832c6f9fdb8353ef..b24e5060bebf901c84678c22244abd04a5e98bb2 100644
--- a/src/ska_tango_base/subarray/subarray_device.py
+++ b/src/ska_tango_base/subarray/subarray_device.py
@@ -47,7 +47,7 @@ class SKASubarray(SKAObsDevice):
             :return: A tuple containing a return code and a string
                 message indicating status. The message is for
                 information purpose only.
-            :rtype: ([ResultCode], [str])
+            :rtype: (ResultCode, str)
             """
             super().do()
 
@@ -96,7 +96,7 @@ class SKASubarray(SKAObsDevice):
             :return: A tuple containing a return code and a string
                 message indicating status. The message is for
                 information purpose only.
-            :rtype: ([ResultCode], [str])
+            :rtype: (ResultCode, str)
             """
             component_manager = self.target
             component_manager.assign(argin)
@@ -143,7 +143,7 @@ class SKASubarray(SKAObsDevice):
             :return: A tuple containing a return code and a string
                 message indicating status. The message is for
                 information purpose only.
-            :rtype: ([ResultCode], [str])
+            :rtype: (ResultCode, str)
             """
             component_manager = self.target
             component_manager.release(argin)