--- a/python/moving.py	Tue Jul 04 18:00:01 2017 -0400
+++ b/python/moving.py	Wed Jul 05 12:19:59 2017 -0400
@@ -682,9 +682,10 @@
     def __getitem__(self, i):
         if isinstance(i, int):
             return Point(self.positions[0][i], self.positions[1][i])
+        elif isinstance(i, slice):
+            return Trajectory([self.positions[0][i],self.positions[1][i]])
         else:
             raise TypeError, "Invalid argument type."
-            #elif isinstance( key, slice ):
 
     def __str__(self):
         return ' '.join([self.__getitem__(i).__str__() for i in xrange(self.length())])
@@ -1091,9 +1092,9 @@
         # compute bounding polygon from trajectory
 
     @staticmethod
-    def generate(p, v, timeInterval):
+    def generate(num, p, v, timeInterval):
         positions, velocities = Trajectory.generate(p, v, int(timeInterval.length())) 
-        return MovingObject(timeInterval = timeInterval, positions = positions, velocities = velocities)
+        return MovingObject(num = num, timeInterval = timeInterval, positions = positions, velocities = velocities)
 
     @staticmethod
     def concatenate(obj1, obj2, num = None):