class_docstr: Test ability to marshall metric protos and invalid input.
class_docstr_tok: ["Test","ability","to","marshall","metric","protos","and","invalid","input","."]
code: def test_help(self):
      st.metric("label_test", value="500", help="   help text")
      c = self.get_delta_from_queue().new_element.metric
      self.assertEqual(c.help, "help text")
  
imports: from parameterized import parameterized
  import streamlit
  from streamlit.errors import StreamlitAPIException
  from streamlit.proto.LabelVisibilityMessage_pb2 import LabelVisibilityMessage
  from streamlit.proto.Metric_pb2 import Metric
  from streamlit.type_util import _LOGGER
  from tests.delta_generator_test_case import DeltaGeneratorTestCase
label_desc: Use image node_id 15 for calling the MetricTest obj's underlying member method code with example usage: obj.test_help() without return types