def get_int_icode(res_seq):
    """
    Return tuple (int, icode) with integer residue sequence number and
    single char icode from PDB residue sequence string such as '60A' or '61'
    etc.

    Parameters:
       res_seq - PDB resisue sequence number string, with or without icode
    Return value:
       tuple (int, icode) where
         int is integer part of res_seq, and icode is char insertino code or None
    """
    if not res_seq[-1].isdigit():
        int1 = int(res_seq[0:len(res_seq)-1])
        icode = res_seq[-1]
    else:
        int1 = int(res_seq)
        icode = None
    return (int1, icode)