Section 121. Acquisition after project approved

When a project has been
  approved, an authority may  purchase,  lease  or  condemn,  or  obligate
  itself  to  purchase,  lease  or  condemn,  real property for a project.
  Notwithstanding any other provisions of and in  addition  to  any  other
  powers  granted  under  this  chapter, where all the dwelling units in a
  building have been leased by an authority for occupancy  by  persons  or
  families  of  low  income  in  accordance with the provisions of section
  twenty-three of the  United  States  housing  act  of  nineteen  hundred
  thirty-seven,  as  amended,  the prior approval by the local legislative
  body of such leasing program shall constitute  all  necessary  approvals
  under  this  chapter  for an authority to exercise an option to purchase
  such real property.