def get_diff_elements(li1, li2):
    """get the elements in li1 but not li2, and vice versa

    Parameters
    ----------
    li1 : list or numpy array
        Input list 1.

    li2 : list or numpy array
        Input list 2.

    Returns
    -------
    difference : list
        The difference between li1 and li2.
    """
    # if isinstance(li1, (np.ndarray, np.generic)):
    #     li1 = li1.tolist()
    # if isinstance(li2, (np.ndarray, np.generic)):
    #     li1 = li1.tolist()

    return (list(set(li1) - set(li2)) + list(set(li2) - set(li1)))
get the elements in li1 but not li2, and vice versa

    Parameters
    ----------
    li1 : list or numpy array
        Input list 1.

    li2 : list or numpy array
        Input list 2.

    Returns
    -------
    difference : list
        The difference between li1 and li2.
    
pyod/utils/utility.py