def get_rb_data_attribute(xmldict, attr):
    """Get Attribute `attr` from dict `xmldict`

    Parameters
    ----------
    xmldict : dict
        Blob Description Dictionary
    attr : str
        Attribute key

    Returns
    -------
    sattr : int
        Attribute Values
    """

    try:
        sattr = int(xmldict["@" + attr])
    except KeyError:
        raise KeyError(
            f"Attribute @{attr} is missing from "
            "Blob Description. There may be some "
            "problems with your file"
        )
    return sattr