pybricks.pupdevices: Avoid class-specific LightArray.

Let's minimize complicated hacks if we can help it.

src/pybricks/_common.py

@@ -605,28 +605,19 @@ class ColorLight:
         """
 
 
-class LightArray:
-    """Control an array of single-color lights."""
+class LightArray3:
+    """Control an array of three single-color lights."""
 
-    def __init__(self, n: int):
-        """LightArray(n)
-
-        Initializes the light array.
-
-        Arguments:
-            n (int): Number of lights
-        """
-
-    def on(self, brightness: Union[Number, Collection[Number]]) -> None:
+    def on(self, brightness: Union[Number, Tuple[Number, Number, Number]]) -> None:
         """on(brightness)
 
         Turns on the lights at the specified brightness.
 
         Arguments:
-            brightness (Number or tuple):
-                Brightness (0--100) of each light, in the order shown above.
-                If you give just one brightness value, all lights get that
-                brightness.
+            brightness (Number or tuple, %):
+                Use a single value to set the brightness of all lights at the
+                same time. Use a tuple of three values to set the brightness
+                of each light individually.
         """
 
     def off(self) -> None:
@@ -635,6 +626,25 @@ class LightArray:
         Turns off all the lights."""
 
 
+class LightArray4(LightArray3):
+    """Control an array of four single-color lights."""
+
+    def on(
+        self, brightness: Union[Number, Tuple[Number, Number, Number, Number]]
+    ) -> None:
+        """on(brightness)
+
+        Turns on the lights at the specified brightness.
+
+        Arguments:
+            brightness (Number or tuple, %):
+                Use a single value to set the brightness of all lights at the
+                same time. Use a tuple of four values to set the brightness
+                of each light individually. The order of the lights is shown
+                in the image above.
+        """
+
+
 class LightMatrix:
     """Control a rectangular grid of single-color lights."""
 

src/pybricks/pupdevices.py

@@ -203,24 +203,7 @@ class PFMotor(DCMotor):
 class ColorSensor(_common.AmbientColorSensor):
     """LEGO® SPIKE Color Sensor."""
 
-    class _LightArray(_common.LightArray):
-        def __init__(self):
-            super().__init__(3)
-
-        def on(self, brightness: Union[Number, Tuple[Number, Number, Number]]) -> None:
-            """on(brightness)
-
-            Turns on the lights at the specified brightness.
-
-            Arguments:
-                brightness (Number or tuple, %):
-                    A single value will set the brightness of all three lights
-                    to the same value. A tuple of 3 values will set the
-                    brightness of each LED individually.
-            """
-            return super().on(brightness)
-
-    lights = _LightArray()
+    lights = _common.LightArray3()
 
     # HACK: jedi can't find inherited __init__ so docs have to be duplicated
     def __init__(self, port: Port):
@@ -234,26 +217,7 @@ class ColorSensor(_common.AmbientColorSensor):
 class UltrasonicSensor:
     """LEGO® SPIKE Color Sensor."""
 
-    class _LightArray(_common.LightArray):
-        def __init__(self):
-            super().__init__(4)
-
-        def on(
-            self, brightness: Union[Number, Tuple[Number, Number, Number, Number]]
-        ) -> None:
-            """on(brightness)
-
-            Turns on the lights at the specified brightness.
-
-            Arguments:
-                brightness (Number or tuple, %):
-                    A single value will set the brightness of all four lights
-                    to the same value. A tuple of 4 values will set the
-                    brightness of each LED individually.
-            """
-            return super().on(brightness)
-
-    lights = _LightArray()
+    lights = _common.LightArray4()
 
     def __init__(self, port: Port):
         """UltrasonicSensor(port)