code: def destroy(self):
          
          for k in list(self.keys()):
              del self[k]
  
          if getattr(self, 'sid_s', None):
              current_app.kvsession_store.delete(self.sid_s)
              self.sid_s = None
  
          self.modified = False
          self.new = False
docs: Destroys a session completely, by deleting all keys and removing it
          from the internal store immediately.
  
          This allows removing a session for security reasons, e.g. a login
          stored in a session will cease to exist if the session is destroyed.