Return created parameter from add_parameter

qcodes/instrument/instrument_base.py

@@ -12,7 +12,9 @@
     Optional,
     Sequence,
     Type,
+    TypeVar,
     Union,
+    cast,
 )
 
 import numpy as np
@@ -29,6 +31,8 @@
 
 log = logging.getLogger(__name__)
 
+TParameter = TypeVar("TParameter", bound=ParameterBase)
+
 
 class InstrumentBase(Metadatable, DelegateAttributes):
     """
@@ -85,9 +89,9 @@ def __init__(self, name: str, metadata: Optional[Mapping[Any, Any]] = None) -> N
     def add_parameter(
         self,
         name: str,
-        parameter_class: Optional[Type[ParameterBase]] = None,
+        parameter_class: Optional[Type[TParameter]] = None,
         **kwargs: Any,
-    ) -> None:
+    ) -> TParameter:
         """
         Bind one Parameter to this instrument.
 
@@ -117,7 +121,7 @@ def add_parameter(
                 one.
         """
         if parameter_class is None:
-            parameter_class = Parameter
+            parameter_class = cast(Type[TParameter], Parameter)
 
         if "bind_to_instrument" not in kwargs.keys():
             kwargs["bind_to_instrument"] = True
@@ -145,6 +149,7 @@ def add_parameter(
                 QCoDeSDeprecationWarning,
             )
             self.parameters[name] = param
+        return param
 
     def add_function(self, name: str, **kwargs: Any) -> None:
         """