code: def pull(self, arm_id, success, failure):
          '''
          Pull arms.
  
          Args:
              arm_id:     Arms master id.
              success:    The number of success.
              failure:    The number of failure.
          '''
          self.__beta_dist_dict[arm_id].observe(success, failuref pull(self, arm_id, success, failure):
          '''
          Pull arms.
  
          Args:
              arm_id:     Arms master id.
              success:    The number of success.
              failure:    The number of failure.
          '''
          self.__beta_dist_dict[arm_id].observe(success, failure)
docs: Pull arms.
  
          Args:
              arm_id:     Arms master id.
              success:    The number of success.
              failure:    The number of failure.