code: def test_wrong_cols(self):
      # Test wrong cols (cols != expected)
      events = pd.DataFrame(
          {
              "c": [5],
              SID_FIELD_NAME: [1],
              TS_FIELD_NAME: [pd.Timestamp("2014")],
              EVENT_DATE_FIELD_NAME: [pd.Timestamp("2014")],
          }
      )
  
      EventsLoader(events, {EventDataSet_US.next_float: "c"}, {})
      EventsLoader(events, {}, {EventDataSet_US.previous_float: "c"})
  
      with self.assertRaises(ValueError) as e:
          EventsLoader(events, {EventDataSet_US.next_float: "d"}, {})
  
      msg = str(e.exception)
      expected = (
          "EventsLoader missing required columns ['d'].\n"
          "Got Columns: ['c', 'event_date', 'sid', 'timestamp']\n"
          "Expected Columns: ['d', 'event_date', 'sid', 'timestamp']"
      )
      self.assertEqual(msg, expected)
  
imports: from datetime import time
  from itertools import product
  from unittest import skipIf
  import blaze
  import numpy
  import pandas
  import pytz
  from zipline.pipeline import Pipeline, SimplePipelineEngine
  from zipline.pipeline.common import EVENT_DATE_FIELD_NAME, TS_FIELD_NAME, SID_FIELD_NAME
  from zipline.pipeline.data import DataSet, Column
  from zipline.pipeline.domain import US_EQUITIES, EquitySessionDomain
  from zipline.pipeline.loaders.events import EventsLoader
  from zipline.pipeline.loaders.blaze.events import BlazeEventsLoader
  from zipline.pipeline.loaders.utils import next_event_indexer, previous_event_indexer
  from zipline.testing import ZiplineTestCase
  from zipline.testing.fixtures import WithAssetFinder, WithTradingSessions
  from zipline.testing.predicates import assert_equal
  from zipline.utils.numpy_utils import categorical_dtype, datetime64ns_dtype, float64_dtype, int64_dtype
  from zipline.utils.pandas_utils import new_pandas, skip_pipeline_new_pandas
label_desc: Use image node_id 8 for calling the EventsLoaderTestCase obj's underlying member method code with example usage: obj.test_wrong_cols() without return types