code: def test_drop_column(self):
      # testing dropping a single column
      seriesA = self.series1.drop_columns("0")
      assert "0" not in seriesA.columns.values
      assert seriesA.columns.tolist() == ["1", "2"]
      assert len(seriesA.columns) == 2
  
      # testing dropping multiple columns
      seriesB = self.series1.drop_columns(["0", "1"])
      assert "2" in seriesB.columns.values
      assert len(seriesB.columns) == 1
  
imports: import numpy
  import pandas
  import pytest
  from darts import TimeSeries
  from darts.tests.test_timeseries import TestTimeSeries
label_desc: Use image node_id 20 for calling the TestTimeSeriesMultivariate obj's underlying member method code with example usage: obj.test_drop_column() without return types