def METHOD_NAME(dbfpath, idvar):
    """Checks duplicates in a ``.dBase`` file ID variable must be specified correctly.
    Author(s) -- Luc Anselin <anselin@uchicago.edu>
    Parameters
    ----------
    dbfpath : str
        The file path to ``.dBase`` file.
    idvar : str
        The ID variable in ``.dBase`` file.
    Returns
    -------
    dups : list
        The duplicate IDs.
    """
    db = ps_open(dbfpath, "r")
    li = db.by_col(idvar)
    dups = list(set([x for x in li if li.count(x) > 1]))
    return dups