code: def testExample2(self):
      with common.CopyFiles(
          [
              os.path.join(
                  "testcases", "data", "30min-bitstampUSD-2.csv"
              )
          ],
          "30min-bitstampUSD.csv",
      ):
          code = """import sys
  sys.path.append('samples')
  import bccharts_example_2
  bccharts_example_2.main(False)
  """
          res = common.run_python_code(code)
          self.assertTrue(res.exit_ok(), res.get_output())
          self.assertEqual(
              res.get_output_lines()[0:10],
              common.head_file(
                  "bccharts_example_2.output", 10, path="testcases/data"
              ),
          )
          self.assertEqual(
              res.get_output_lines()[-10:],
              common.tail_file(
                  "bccharts_example_2.output", 10, path="testcases/data"
              ),
          )
  
imports: import os
  import six
  from testcases import common
label_desc: Use image node_id 2 for calling the BitcoinChartsTestCase obj's underlying member method code with example usage: obj.testExample2() without return types