code: def test_ohlc4(self):
      result = pandas_ta.ohlc4(
          self.open, self.high, self.low, self.close
      )
      self.assertIsInstance(result, Series)
      self.assertEqual(result.name, "OHLC4")
  
imports: from .config import CORRELATION, CORRELATION_THRESHOLD, error_analysis, sample_data, VERBOSE
  from .context import pandas_ta
  from unittest import TestCase
  import pandas.testing
  from pandas import DataFrame, Series
  import talib
label_desc: Use image node_id 26 for calling the TestOverlap obj's underlying member method code with example usage: obj.test_ohlc4() without return types