def unique_routes(routes):
    """
    Returns an list with unique routes for all nodes.
    This function achieves this by removing simetrical
    routes (A, B, C) == (C, B, A).

    Args:
        routes - a list of routes, as sequences of nodes
        
    Returns: An list with unique routes.
    """

    # Iterate over all routes in reversed order
    for route in list(reversed(routes)):
        
        # If the reversed route (C, B, A) exists in the list
        if list(reversed(route)) in routes:
            
            # Remove it from the list
            routes.remove(route)
            
    return routes