def load_taxids(infile):
    """
    Loading taxids; assuming 1 per line
    """
    if infile is None:
        return None
    taxids = set()
    with open(infile) as inF:
        for line in inF:
            line = line.rstrip().split('\t')
            if line[0] == '':
                continue
            taxids.add(int(line[0]))
    return taxids