Replace placeholder code with '...'.

src/morse_code.py

@@ -34,4 +34,4 @@ def translate_message(morse: str) -> str:
         encountered, they are ignored. If the last potential symbol is not 
         valid, it is appended as is (i.e., as dots and dashes).
     """
-    return None
+    ...

src/morse_engine.py

@@ -25,7 +25,7 @@ def set_color(elapsed_t: float, px: LEDController):
         elapsed_t (float): duration of proximity detection.
         px : LED controller object.
     """
-    pass
+    ...
 
 
 def add_mark(elapsed_t: float) -> str:
@@ -39,7 +39,7 @@ def add_mark(elapsed_t: float) -> str:
     Returns:
         str: dot (.), dash (-), or empty ("").
     """
-    pass
+    ...
 
 
 def run_morse_engine(apds: ProximitySensor, pixels: LEDController, touch: TouchSensor):

src/prox_pulse.py

@@ -17,7 +17,7 @@ def prox_pulse(px: LEDController, color: tuple[int, int, int], prox: int) -> Non
         color (tuple): color to pulse.
         prox (int): proximity value.
     """
-    pass  # Delete this line when you start coding!
+    ...
 
 
 def run_prox_pulse(apds: ProximitySensor, pixels: LEDController) -> None:

src/pulse.py

@@ -16,7 +16,7 @@ def pulse(px: LEDController, color: tuple[int, int, int], duration: float):
         color (tuple): Color to display.
         duration (float): time in seconds to keep the color on/off.
     """
-    pass  # Delete this line when you start coding!
+    ...
 
 
 def run_simple_pulse(pixels: LEDController):