def squash_bojone(x, axis=-1):
    """
       activation of squash
    :param x: vector
    :param axis: int
    :return: vector
    """
    s_squared_norm = K.sum(K.square(x), axis, keepdims=True)
    scale = K.sqrt(s_squared_norm + K.epsilon())
    return x / scale

       activation of squash
    :param x: vector
    :param axis: int
    :return: vector
    
keras_textclassification/keras_layers/capsule.py