code: def _validate_benchmark(self, benchmark_asset):
      # check if this security has a stock dividend.  if so, raise an
      # error suggesting that the user pick a different asset to use
      # as benchmark.
      stock_dividends = self.data_portal.get_stock_dividends(
          self.benchmark_asset, self.sessions
      )
  
      if len(stock_dividends) > 0:
          raise InvalidBenchmarkAsset(
              sid=str(self.benchmark_asset),
              dt=stock_dividends[0]["ex_date"],
          )
  
      if benchmark_asset.start_date > self.sessions[0]:
          # the asset started trading after the first simulation day
          raise BenchmarkAssetNotAvailableTooEarly(
              sid=str(self.benchmark_asset),
              dt=self.sessions[0],
              start_dt=benchmark_asset.start_date,
          )
  
      if benchmark_asset.end_date < self.sessions[-1]:
          # the asset stopped trading before the last simulation day
          raise BenchmarkAssetNotAvailableTooLate(
              sid=str(self.benchmark_asset),
              dt=self.sessions[-1],
              end_dt=benchmark_asset.end_date,
          )
  
file_path: catalyst/catalyst/sources/benchmark_source.py
imports: import pandas
  from catalyst.errors import InvalidBenchmarkAsset, BenchmarkAssetNotAvailableTooEarly, BenchmarkAssetNotAvailableTooLate
label_desc: Use image node_id 4 for calling the BenchmarkSource obj's underlying member method code with example usage: obj._validate_benchmark(benchmark_asset) without return types