feat: is connect checks decorators (#2813)

src/lerobot/utils/decorators.py

@@ -0,0 +1,41 @@
+#!/usr/bin/env python
+
+# Copyright 2026 The HuggingFace Inc. team. All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from functools import wraps
+
+from lerobot.utils.errors import DeviceAlreadyConnectedError, DeviceNotConnectedError
+
+
+def check_if_not_connected(func):
+    @wraps(func)
+    def wrapper(self, *args, **kwargs):
+        if not self.is_connected:
+            raise DeviceNotConnectedError(
+                f"{self.__class__.__name__} is not connected. Run `.connect()` first."
+            )
+        return func(self, *args, **kwargs)
+
+    return wrapper
+
+
+def check_if_already_connected(func):
+    @wraps(func)
+    def wrapper(self, *args, **kwargs):
+        if self.is_connected:
+            raise DeviceAlreadyConnectedError(f"{self.__class__.__name__} is already connected.")
+        return func(self, *args, **kwargs)
+
+    return wrapper