Does not crash if invalid connection

Author: kjy5

src/ephys_link/bindings/ump_binding.py

@@ -34,21 +34,6 @@ def __init__(self) -> None:
         UMP.set_library_path(RESOURCES_DIRECTORY)
         self._ump: UMP = UMP.get_ump()  # pyright: ignore [reportUnknownMemberType]
 
-        # Exit if no manipulators are connected.
-        device_ids: list[str] = list(map(str, self._ump.list_devices()))
-        if len(device_ids) == 0:
-            msg = "No manipulators connected."
-            raise RuntimeError(msg)
-
-        # Currently only supports using uMp-4 XOR uMp-3. Exit if both are connected.
-
-        # Use the first device as the reference for the number of axes.
-        self.num_axes: int = self._get_device(device_ids[0]).n_axes()
-
-        if any(self._get_device(device_id).n_axes() != self.num_axes for device_id in device_ids):  # pyright: ignore [reportUnknownArgumentType, reportUnknownMemberType]
-            msg = "uMp-4 and uMp-3 cannot be used at the same time."
-            raise RuntimeError(msg)
-
     @staticmethod
     @override
     def get_display_name() -> str:
@@ -61,11 +46,31 @@ def get_cli_name() -> str:
 
     @override
     async def get_manipulators(self) -> list[str]:
-        return list(map(str, self._ump.list_devices()))
+        device_ids = list(map(str, self._ump.list_devices()))
+        
+        # Shortcut for empty device list.
+        if len(device_ids) == 0:
+            return []
+        
+        first_device_axis_count = self._get_device(device_ids[0]).n_axes() 
+
+        # Currently only supports using uMp-4 XOR uMp-3. Throw error if both are connected.
+        if any(self._get_device(device_id).n_axes() != first_device_axis_count for device_id in device_ids):  # pyright: ignore [reportUnknownArgumentType, reportUnknownMemberType]
+            msg = "uMp-4 and uMp-3 cannot be used at the same time."
+            raise RuntimeError(msg)
+        
+        return device_ids
 
     @override
     async def get_axes_count(self) -> int:
-        return self.num_axes
+        device_ids = await self.get_manipulators()
+        
+        # If no manipulators are connected, return 0.
+        if len(device_ids) == 0:
+            return 0
+        
+        # If multiple manipulators are connected, return the number of axes of the first one.
+        return self._get_device(device_ids[0]).n_axes()
 
     @override
     def get_dimensions(self) -> Vector4:
@@ -236,4 +241,4 @@ def _is_ump_3(self) -> bool:
         Returns:
             True if the device is uMp-3, False otherwise.
         """
-        return self.num_axes == self.UMP_3_NUM_AXES
+        return self.get_axes_count() == self.UMP_3_NUM_AXES