def parse_contig_assignments(assignment_file_path, contig_name_col=0, unassigned_col=9):
    """
    Finds contig_names that are unassigned twice.

    Inputs:
    - assignment_file_path: Path to tab-delimited file
    - contig_name_col: Index of the col which will have the contig name
    - unassigned_col: Index of the col which will say if it is unassigned, i.e.
        will say 'UNASSIGNED'

    Output: A set of contig names where there are n unassigned lines.

    """
    traking = set()
    unassigned = set()
    with open(assignment_file_path) as infile_handle:

        for line in infile_handle:
            line = line.split("\t")

            contig_name = line[contig_name_col]
            unassigned_status = line[unassigned_col]

            if unassigned_status == "UNASSIGNED":

                if contig_name in traking:
                    unassigned.add(contig_name)

                else:
                    traking.add(contig_name)

    return unassigned