I'm not seeing anything on the FTP website that has this info: ftp://ftp.ensembl.org/pub/release-94/fasta/homo_sapiens/

My main goal is to get the exons in uppercase and the introns in lowercase. I tried using this but it dot work for many of the identifiers and takes a long time:

# Download Ensembl Sequences
def download_ensembl(ids, path_fasta="./premrna.fa", mode="premrna", file_log=sys.stderr, drop_N=True):
    """
    Download transcript sequences to `path_fasta`.  Can be either `premrna` or `cds`.
    Ensembl REST API

    """
    server = "https://rest.ensembl.org"
    # Create file handle
    if type(path_fasta) == str:
        handle = open(path_fasta, "w")
    else:
        handle = path_fasta

    with handle as f:
        for id in tqdm(ids):
            if mode == "premrna":
                ext = "/sequence/id/" + id + "?content-type=text/plain;mask_feature=1"
            if mode == "cds":
                ext = "/sequence/id/" + id + "?type=cds"
            try:
                r = requests.get(server+ext, headers={ "Content-Type" : "text/x-fasta"})
                if not r.ok:
                    r.raise_for_status()
                seq_record = r.text.split("\n")
                id = seq_record[0][1:]
                seq = "".join(seq_record[1:])
                if drop_N:
                    seq = seq.replace("n","").replace("N","")
                print(">%s\n%s"%(id,seq), file=f)
            except requests.HTTPError:
                print("\nHTTPError: Invalid identifier `%s`"%(id), file=file_log)
    if handle is not sys.stderr:
        handle.close()