Searches a base element for subelement by name, then takes the
    cvParams of that subelement and returns the values as a list
    for the paramnames that match. Value order in list equals input
    paramnames order.

def fetch_cvparams_values_from_subel(base, subelname, paramnames, ns):
    """Searches a base element for subelement by name, then takes the
    cvParams of that subelement and returns the values as a list
    for the paramnames that match. Value order in list equals input
    paramnames order."""
    sub_el = basereader.find_element_xpath(base, subelname, ns)
    cvparams = get_all_cvparams(sub_el, ns)
    output = []
    for param in paramnames:
        output.append(fetch_cvparam_value_by_name(cvparams, param))
    return output