def get_qual(fastafile, suffix=QUALSUFFIX, check=True):
    """
    Check if current folder contains a qual file associated with the fastafile
    """
    qualfile1 = fastafile.rsplit(".", 1)[0] + suffix
    qualfile2 = fastafile + suffix

    if check:
        if op.exists(qualfile1):
            logging.debug("qual file `{0}` found".format(qualfile1))
            return qualfile1
        elif op.exists(qualfile2):
            logging.debug("qual file `{0}` found".format(qualfile2))
            return qualfile2
        else:
            logging.warning("qual file not found")
            return None

    return qualfile1
Check if current folder contains a qual file associated with the fastafile