code: def request_permission(cls, fine=True):
          
          app = AndroidApplication.instance()
          permission = (cls.ACCESS_FINE_PERMISSION
                        if fine else cls.ACCESS_COARSE_PERMISSION)
          f = app.create_future()
  
          def on_result(perms):
              app.set_future_result(f, perms[permission])
  
          app.request_permissions([permission]).then(on_result)
  
          return f
docs: Requests permission and returns an async result that returns 
          a boolean indicating if the permission was granted or denied.