Section 28-401.4. Requirement of license

It shall be unlawful for any person
  to engage in or carry on in the city any business, trade  or  occupation
  regulated  by  this  chapter  or  to  hold  himself  or  herself  out as
  authorized to engage in or carry on such activity, without having  first
  obtained  a license from the commissioner in accordance with and subject
  to the provisions of this chapter and the rules  of  the  department.  A
  license  issued  by  the  department  for  any  such  business, trade or
  occupation prior to the effective date of this  code,  shall  remain  in
  full  force  and  effect  until the expiration or termination thereof in
  accordance with the terms thereof, unless sooner  revoked  or  suspended
  for  cause as hereinafter provided. Any renewal of such license shall be
  in accordance with the provisions of this code.