code: def test_multiple_named_namespaces():
      df = pd.DataFrame({"y": [1], "a": [2], "b": [3]})
      conv = DFtoVW(
          df=df,
          label=SimpleLabel("y"),
          namespaces=[
              Namespace(name="FirstNameSpace", features=Feature("a")),
              Namespace(
                  name="DoubleIt", value=2, features=Feature("b")
              ),
          ],
      )
      first_line = conv.convert_df()[0]
      assert first_line == "1 |FirstNameSpace a:2 |DoubleIt:2 b:3"
  
imports: import pytest
  import pandas
  from vowpalwabbit.dftovw import ContextualbanditLabel, DFtoVW, Feature, MulticlassLabel, MultiLabel, Namespace, SimpleLabel
label_desc: Use image node_id 13 for calling a global function with example usage: test_multiple_named_namespaces() without return types