import re


def IsJunk(contig):
    """returns true, if contigs is likely to be junk.

    This is done by name matching. Junk contigs contain either
    one of the following:

    random, unknown, chrU, chU.
    """

    c = contig.lower()
    negative_list = "random", "unknown", "chru", "chu"

    for x in negative_list:
        if re.search(x, c):
            return True

    return False