def aggregate_values(values_list, values_keys):
    """
    Returns a string with concatenated values based on a dictionary values and a list of keys
    :param dict values_list: The dictionary to get values from
    :param str[] values_keys: A list of strings to be used as keys
    :return str:
    """
    output = ""
    for key in values_keys:
        output += values_list.get(key, "")
    return output