fix: further clean-up in controlled.py

pennylane/ops/op_math/controlled.py

@@ -42,16 +42,20 @@ def ctrl(
     op: Operator,
     control: Any,
     control_values: Optional[Sequence[bool]] = None,
-    work_wires: Optional[Any] = None,
+    work_wires: Optional[Any] = (),
 ) -> Operator: ...
+
+
 @overload
 def ctrl(
     op: Callable,
     control: Any,
     control_values: Optional[Sequence[bool]] = None,
-    work_wires: Optional[Any] = None,
+    work_wires: Optional[Any] = (),
 ) -> Callable: ...
-def ctrl(op, control: Any, control_values=None, work_wires=None):
+
+
+def ctrl(op, control: WiresLike, control_values=None, work_wires: WiresLike = ()):
     """Create a method that applies a controlled version of the provided op.
     :func:`~.qjit` compatible.
 
@@ -148,7 +152,7 @@ def cond_fn():
     return create_controlled_op(op, control, control_values=control_values, work_wires=work_wires)
 
 
-def create_controlled_op(op, control, control_values=None, work_wires: WiresLike = ()):
+def create_controlled_op(op, control: WiresLike, control_values=None, work_wires: WiresLike = ()):
     """Default ``qml.ctrl`` implementation, allowing other implementations to call it when needed."""
 
     control = Wires(control)
@@ -201,7 +205,7 @@ def create_controlled_op(op, control, control_values=None, work_wires: WiresLike
     return _ctrl_transform(op, control, control_values, work_wires)
 
 
-def _ctrl_transform(op, control, control_values, work_wires):
+def _ctrl_transform(op, control: WiresLike, control_values, work_wires: WiresLike):
     @wraps(op)
     def wrapper(*args, **kwargs):
         qscript = qml.tape.make_qscript(op)(*args, **kwargs)
@@ -261,7 +265,9 @@ def _(*_, **__):
     return ctrl_prim
 
 
-def _capture_ctrl_transform(qfunc: Callable, control, control_values, work_wires) -> Callable:
+def _capture_ctrl_transform(
+    qfunc: Callable, control: WiresLike, control_values, work_wires: WiresLike
+) -> Callable:
     """Capture compatible way of performing an ctrl transform."""
     # note that this logic is tested in `tests/capture/test_nested_plxpr.py`
     import jax  # pylint: disable=import-outside-toplevel
@@ -341,7 +347,7 @@ def _try_wrap_in_custom_ctrl_op(
 
 
 def _handle_pauli_x_based_controlled_ops(
-    op, control: WiresLike, control_values, work_wires: WiresLike = None
+    op, control: WiresLike, control_values, work_wires: WiresLike = ()
 ):
     """Handles PauliX-based controlled operations."""
 
@@ -486,7 +492,12 @@ def __new__(cls, base, *_, **__):
     # pylint: disable=arguments-differ
     @classmethod
     def _primitive_bind_call(
-        cls, base, control_wires, control_values=None, work_wires=None, id=None
+        cls,
+        base,
+        control_wires: WiresLike,
+        control_values=None,
+        work_wires: WiresLike = (),
+        id=None,
     ):
         control_wires = Wires(control_wires)
         return cls._primitive.bind(
@@ -499,7 +510,7 @@ def __init__(
         base,
         control_wires: WiresLike,
         control_values=None,
-        work_wires: WiresLike = None,
+        work_wires: WiresLike = (),
         id=None,
     ):
         control_wires = Wires(control_wires)
@@ -663,17 +674,17 @@ def _compute_matrix_from_base(self):
 
         return qmlmath.block_diag([left_pad, base_matrix, right_pad])
 
-    def matrix(self, wire_order=None):
+    def matrix(self, wire_order: WiresLike = None):
         if self.compute_matrix is not Operator.compute_matrix:
             canonical_matrix = self.compute_matrix(*self.data)
         else:
             canonical_matrix = self._compute_matrix_from_base()
 
-        wire_order = wire_order or self.wires
+        wire_order = self.wires if wire_order is None else wire_order
         return qml.math.expand_matrix(canonical_matrix, wires=self.wires, wire_order=wire_order)
 
     # pylint: disable=arguments-differ
-    def sparse_matrix(self, wire_order=None, format="csr"):
+    def sparse_matrix(self, wire_order: WiresLike = None, format="csr"):
         if wire_order is not None:
             raise NotImplementedError("wire_order argument is not yet implemented.")
 
@@ -925,7 +936,14 @@ def __new__(cls, *_, **__):
         return object.__new__(cls)
 
     # pylint: disable=too-many-function-args
-    def __init__(self, base, control_wires, control_values=None, work_wires=None, id=None):
+    def __init__(
+        self,
+        base,
+        control_wires: WiresLike,
+        control_values=None,
+        work_wires: WiresLike = None,
+        id=None,
+    ):
         super().__init__(base, control_wires, control_values, work_wires, id)
         # check the grad_recipe validity
         if self.grad_recipe is None:
@@ -975,7 +993,7 @@ def parameter_frequencies(self):
 if Controlled._primitive is not None:  # pylint: disable=protected-access
 
     @Controlled._primitive.def_impl  # pylint: disable=protected-access
-    def _(base, *control_wires, control_values=None, work_wires=None, id=None):
+    def _(base, *control_wires, control_values=None, work_wires: WiresLike = None, id=None):
         return type.__call__(
             Controlled,
             base,