def join_neighs_OR_notrelpos(idxs0_ki, idxs1_ki):
    """Join neighs with OR.

    Parameters
    ----------
    idxs0_ki: list or np.ndarray
        the indices of the neighs of neighbourhood0
    idxs1_ki: list or np.ndarray
        the indices of the neighs of neighbourhood1

    Returns
    -------
    neighs: list
        the joined neighbourhood.

    """
    neighs = []
    for i in range(len(idxs0_ki)):
        neighs.append(idxs0_ki[i])
    for i in range(len(idxs1_ki)):
        if idxs1_ki[i] not in idxs0_ki:
            neighs.append(idxs1_ki[i])
    return neighs