docs: def regenerate(self):
          """Regenerate the session id.
  
          This function creates a new session id and stores all information
          associated with the current id in that new id. It then destroys the
          old session id. This is useful for preventing session fixation attacks
          and should be done whenever someone uses a login to obtain additional
          authorizaiton.
          """
  
          oldhash = self.session_hash
          self.new_session_id()
          try:
              self.rdb.rename(oldhash,self.session_hash)
              self.rdb.expire(self.session_hash,self.ttl)
          except:
              pass