def add(vec0, vec1):
    """Adds two vectors."""
    x0, y0 = vec0
    x1, y1 = vec1
    return (x0 + x1, y0 + y1)

def get_occupant(game, position):
    """Returns the agent at position, if there is one."""
    positions_with_agents = game.get_agents_by_position()
    if position in positions_with_agents:
        agents_at_position = positions_with_agents[position]
        return agents_at_position[0]

def distance(vec0, vec1):
    """Returns the Manhattan distance between two positions."""
    x0, y0 = vec0
    x1, y1 = vec1
    return abs(x1 - x0) + abs(y1 - y0)