def prefixKeys(data, prefix, separator):
    """Prefix dictionary keys

    :param data: dictionary of data
    :param prefix: value to prefix keys with
    :param separator: character between prefix and original key name
    :returns: prefixed - dictionary with updated key names
    """
    prefixed = {}
    if type(data) is dict:
        for key in data.keys():
            newKeyName = f"{prefix}{separator}{key}"
            prefixed[newKeyName] = data[key]
    return prefixed