Fix up some more commenting

tracking/algorithms.py

@@ -136,6 +136,19 @@ def calc_groups(scan):
 
 
 def find_centre(group):
+    """
+    Gets a tuple (x,y) of the centre of the group.
+
+    Parameters
+    ----------
+    group: Group
+        A group of points to find the centre of.
+
+    Returns
+    -------
+    tuple (x,y)
+        The centre in the form of a tuple (x,y)
+    """
     return ((group.get_maxX() + group.get_minX()) / 2, (group.get_maxY() + group.get_minY()) / 2)
 
 
@@ -159,8 +172,21 @@ def updateCarVelocity(oldGroup, newGroup):
     Return a tuple (DistanceChange, AngleChange) indicating how the tracked groups have changed, which can
     be used to then update the steering/throttle of the car (or other vehicle that
     may be used)
+
+    Parameters
+    ----------
+    oldGroup: Group
+        The positioning of points for the group in the last scan.
+
+    newGroup: Group
+        The positioning of points for the group in the latest scan.
+
+    Returns
+    -------
+    tuple (DistanceChange, AngleChange)
+        A tuple containing how the groups' centres changed in the form (distance,angle)
     """
-    pass
+    return (find_centre(newGroup))
 
 
 def dualServoChange(newCentre, changeTuple):