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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def _get_s3_files(local_dir, file_info, params):
 """Retrieve s3 files to local directory, handling STORMSeq inputs. """

    assert len(file_info) == 1
    files = file_info.values()[0]
    fnames = []
    for k in ["1", "2"]:
        if files[k] not in fnames:
            fnames.append(files[k])
    out = []
    for fname in fnames:
        bucket, key = fname.replace("s3://", "").split("/", 1)
        if params["access_key_id"] == "TEST":
            out.append(os.path.join(local_dir, os.path.basename(key)))
        else:
            out.append(s3.get_file(local_dir, bucket, key, params))
    return out