check the first 100 reads to see if a FASTQ file has already been transformed
    by umis

def is_transformed(fastq):
    """
    check the first 100 reads to see if a FASTQ file has already been transformed
    by umis
    """

    with open_fastq(fastq) as in_handle:
        for line in islice(in_handle, 400):
            if "UMI_" in line:
                return True
    return False