code: def step_all(self):
      from metaflow import current
  
      assert_equals(len(current.parameter_names), 1)
      assert_equals(current.parameter_names[0], "foo")
  
imports: from metaflow_test import MetaflowTest, steps
label_desc: Use image node_id 1 for calling the ParameterNameTest obj's underlying member method code with example usage: obj.step_all() without return types