Identify all ControlGroupEvent update_types

sc2reader/events/game.py

@@ -521,17 +521,21 @@ def __str__(self):
 
 def create_control_group_event(frame, pid, data):
     update_type = data["control_group_update"]
-    if update_type == 0:
+    if update_type in [0, 4]:
+        # 0 is the normal set command.
+        # 4 is used when you steal and set. If required, type 4 will be followed by autogenerated
+        # selection and control group events that remove the units from their other groups.
         return SetControlGroupEvent(frame, pid, data)
-    elif update_type == 1:
+    elif update_type in [1, 5]:
+        # 1 is the normal add command.
+        # 5 is used when you steal and add. If required, type 5 will be followed by autogenerated
+        # selection and control group events that remove the units from their other groups.
         return AddToControlGroupEvent(frame, pid, data)
     elif update_type == 2:
         return GetControlGroupEvent(frame, pid, data)
     elif update_type == 3:
-        # TODO: What could this be?!?
-        return ControlGroupEvent(frame, pid, data)
+        return DeleteControlGroupEvent(frame, pid, data)
     else:
-        # No idea what this is but we're seeing update_types of 4 and 5 in 3.0
         return ControlGroupEvent(frame, pid, data)
 
 
@@ -589,6 +593,15 @@ class AddToControlGroupEvent(SetControlGroupEvent):
     """
 
 
+class DeleteControlGroupEvent(ControlGroupEvent):
+    """
+    Extends :class:`ControlGroupEvent`
+
+    This event deletes the control group (all units are removed). This happens when all
+    units are stolen from the event group (alt, alt+shift modifiers by default).
+    """
+
+
 class GetControlGroupEvent(ControlGroupEvent):
     """
     Extends :class:`ControlGroupEvent`