class_docstr: For when we don't care about keeping track of the number of tokens.
class_docstr_tok: ["For","when","we","do","n't","care","about","keeping","track","of","the","number","of","tokens","."]
docstr: No need to estimate tokens, since it's free. Return 0.
docstr_tok: ["No","need","to","estimate","tokens",",","since","it","'s","free",".","Return","0","."]
code: def estimate_tokens(
      self, request: Request, metric_service: MetricService
  ) -> int:
      """No need to estimate tokens, since it's free. Return 0."""
      return 0
  
imports: from helm.benchmark.metrics.metric_service import MetricService
  from helm.common.request import Request
  from .token_cost_estimator import TokenCostEstimator
label_desc: Use image node_id 1 for calling the FreeTokenCostEstimator obj's underlying member method code with example usage: obj.estimate_tokens(request, metric_service) and returns: int