code: def test_multilabel():
      df = pd.DataFrame({"y1": [1], "y2": [2], "x": [3]})
      conv = DFtoVW(
          df=df, label=MultiLabel(["y1", "y2"]), features=Feature("x")
      )
      first_line = conv.convert_df()[0]
      assert first_line == "1,2 | x:3"
  
imports: import pytest
  import pandas
  from vowpalwabbit.dftovw import ContextualbanditLabel, DFtoVW, Feature, MulticlassLabel, MultiLabel, Namespace, SimpleLabel
label_desc: Use image node_id 24 for calling a global function with example usage: test_multilabel() without return types