No association, or method or act thereof which complies with this chapter, shall be deemed a conspiracy or combination in restraint of trade or an illegal monopoly, or an attempt to lessen competition or fix prices arbitrarily, or the creation of a combination or pool, or to accomplish any improper or illegal purpose. Any agreements authorized under this chapter shall not be considered as illegal, in restraint of trade, or as part of a conspiracy or combination to accomplish an illegal purpose or act.