code: def setup_method(self, method):
      self._token_cost_estimator = AI21TokenCostEstimator()
  
imports: from unittest.mock import Mock
  from helm.common.request import Request
  from .ai21_token_cost_estimator import AI21TokenCostEstimator
label_desc: Use image node_id 1 for calling the TestAI21TokenCostEstimator obj's underlying member method code with example usage: obj.setup_method(method) without return types