code: def test_namespace_with_value_but_no_name():
      with pytest.raises(ValueError) as value_error:
          Namespace(features=Feature("a"), value=10)
      expected = "Namespace can't have a 'value' argument without a 'name' argument or an empty string 'name' argument"
      assert expected == str(value_error.value)
  
imports: import pytest
  import pandas
  from vowpalwabbit.dftovw import ContextualbanditLabel, DFtoVW, Feature, MulticlassLabel, MultiLabel, Namespace, SimpleLabel
label_desc: Use image node_id 4 for calling a global function with example usage: test_namespace_with_value_but_no_name() without return types