def check_dups(li):
    """checks duplicates in list of ID values
       ID values must be read in as a list

       __author__  = "Luc Anselin <luc.anselin@asu.edu> "
       
       Arguments
       ---------
       li      : list of ID values
       
       Returns
       -------
       a list with the duplicate IDs
    """
    return list(set([x for x in li if li.count(x) > 1]))