docstr: Checking all elements in case LabelledData.label is redefined
docstr_tok: ["Checking","all","elements","in","case","LabelledData.label","is","redefined"]
code: def test_element_label_parameter_declared_constant(self):
      """
      Checking all elements in case LabelledData.label is redefined
      """
      for element_name in all_elements:
          el = getattr(element, element_name)
          self.assertEqual(
              el.param["label"].constant,
              True,
              msg=f"Label parameter of element {element_name} not constant",
          )
  
imports: from holoviews import element
  from holoviews.element import __all__
  from holoviews.element.comparison import ComparisonTestCase
label_desc: Use image node_id 2 for calling the TestParameterDeclarations obj's underlying member method code with example usage: obj.test_element_label_parameter_declared_constant() without return types