def distance_between_nodes(x, y):
    """
    Return the distance between two pynodes.
    """
    ax, ay, az = x.getTranslation(space="world")
    bx, b, bz = y.getTranslation(space="world")
    return ((ax - bx) ** 2 + (ay - b) ** 2 + (az - bz) ** 2) ** 0.5