def METHOD_NAME(constraint_string):
    m = _pattern_timesby.match(constraint_string)
    if m is None:
        raise ValueError("Constraint " + constraint_string + " not understood")
    cv, ex, fac = m.groups()
    if ex is None:
        cv = float(cv)
    else:
        cv = float(cv + ex)
    return cv, float(fac)