Catmandu::Fix::retain - delete everything except the paths given

       Catmandu::Fix::retain - delete everything except the paths given

       Catmandu::Fix

perl v5.40.0                                       2025-01-17                         Catmandu::Fix::retain(3pm)

          # Keep the field _id , name , title
          retain(_id , name, title)

          # Delete everything except foo.bar
          #   {bar => { x => 1} , foo => {bar => 1, y => 2}}
          # to
          #   {foo => {bar => 1}}
          retain(foo.bar)