def all_uni_present(uni_list, uniprot_folder):
    uni_missing = []
    progress = ProgressBar(
        len(uni_list),
        start_msg="Verify that UniProt IDs are identical between DataFrames.",
        end_msg="Verification complete."
    )
    for uni in uni_list:
        uni_path = os.path.join(uniprot_folder, uni + '.fasta')
        if not os.path.exists(uni_path):
            uni_missing.append(uni)
        else:
            try:
                with open(uni_path, 'r', encoding='utf-8') as uni_fh:
                    _ = SeqIO.read(uni_fh, "fasta").seq
            except ValueError:
                os.remove(uni_path)
                uni_missing.append(uni)
        progress.inc()
    return uni_missing