Remove positional arguments in QSVC/QSVR (#535)

* remove positional arguments

* add reno

qiskit_machine_learning/algorithms/classifiers/qsvc.py

@@ -42,21 +42,13 @@ class QSVC(SVC, SerializableModelMixin):
         qsvc.predict(sample_test)
     """
 
-    def __init__(self, *args, quantum_kernel: Optional[BaseKernel] = None, **kwargs):
+    def __init__(self, *, quantum_kernel: Optional[BaseKernel] = None, **kwargs):
         """
         Args:
             quantum_kernel: Quantum kernel to be used for classification.
             *args: Variable length argument list to pass to SVC constructor.
             **kwargs: Arbitrary keyword arguments to pass to SVC constructor.
         """
-        if (len(args)) != 0:
-            msg = (
-                f"Positional arguments ({args}) are deprecated as of version 0.3.0 and "
-                f"will be removed no sooner than 3 months after the release. Instead use "
-                f"keyword arguments."
-            )
-            warnings.warn(msg, DeprecationWarning, stacklevel=2)
-
         if "kernel" in kwargs:
             msg = (
                 "'kernel' argument is not supported and will be discarded, "
@@ -71,7 +63,7 @@ def __init__(self, *args, quantum_kernel: Optional[BaseKernel] = None, **kwargs)
         if "random_state" not in kwargs:
             kwargs["random_state"] = algorithm_globals.random_seed
 
-        super().__init__(kernel=self._quantum_kernel.evaluate, *args, **kwargs)
+        super().__init__(kernel=self._quantum_kernel.evaluate, **kwargs)
 
     @property
     def quantum_kernel(self) -> BaseKernel:

qiskit_machine_learning/algorithms/regressors/qsvr.py

@@ -41,21 +41,13 @@ class QSVR(SVR, SerializableModelMixin):
         qsvr.predict(sample_test)
     """
 
-    def __init__(self, *args, quantum_kernel: Optional[BaseKernel] = None, **kwargs):
+    def __init__(self, *, quantum_kernel: Optional[BaseKernel] = None, **kwargs):
         """
         Args:
             quantum_kernel: Quantum kernel to be used for regression.
             *args: Variable length argument list to pass to SVR constructor.
             **kwargs: Arbitrary keyword arguments to pass to SVR constructor.
         """
-        if (len(args)) != 0:
-            msg = (
-                f"Positional arguments ({args}) are deprecated as of version 0.3.0 and "
-                f"will be removed no sooner than 3 months after the release. Instead use "
-                f"keyword arguments."
-            )
-            warnings.warn(msg, DeprecationWarning, stacklevel=2)
-
         if "kernel" in kwargs:
             msg = (
                 "'kernel' argument is not supported and will be discarded, "
@@ -67,7 +59,7 @@ def __init__(self, *args, quantum_kernel: Optional[BaseKernel] = None, **kwargs)
 
         self._quantum_kernel = quantum_kernel if quantum_kernel else FidelityQuantumKernel()
 
-        super().__init__(kernel=self._quantum_kernel.evaluate, *args, **kwargs)
+        super().__init__(kernel=self._quantum_kernel.evaluate, **kwargs)
 
     @property
     def quantum_kernel(self) -> BaseKernel:

releasenotes/notes/remove-qsvc-qsvr-positional-arguments-36394f2da1a4ae17.yaml

@@ -0,0 +1,7 @@
+---
+deprecations:
+  - |
+    Positional arguments in :class:`~qiskit_machine_learning.algorithms.QSVC` and
+    :class:`~qiskit_machine_learning.algorithms.QSVR` were deprecated as of version 0.3. Support of
+    the positional arguments was completely removed in this version, please replace them with
+    corresponding keyword arguments.