import time


def elapsed(earlier, later):
    """elapsed - Convert elapsed time.time objects to duration string
    
    Useful for tracking move and game time.  Example pseudocode:
    
    gamestart = time.time()
    
    while game not over:
        movestart = time.time()
        ...  logic ...
        current = time.time() 
        print("Move time: {} Game time: {}".format(
            elapsed(movestart, current), elapsed(gamestart, current))
    
    
    """
    return time.strftime('%H:%M:%S', time.gmtime(later - earlier))