Address comments

lerobot/common/robot_devices/cameras/opencv.py

@@ -272,7 +272,9 @@ class OpenCVCamera:
         actual_width = self.camera.get(cv2.CAP_PROP_FRAME_WIDTH)
         actual_height = self.camera.get(cv2.CAP_PROP_FRAME_HEIGHT)
 
+        # Using `math.isclose` since actual fps can be a float (e.g. 29.9 instead of 30)
         if self.fps is not None and not math.isclose(self.fps, actual_fps, rel_tol=1e-3):
+            # Using `OSError` since it's a broad that encompasses issues related to device communication
             raise OSError(
                 f"Can't set {self.fps=} for OpenCVCamera({self.camera_index}). Actual value is {actual_fps}."
             )