code: def test_theme(self, theme_value, proto_value):
      df = px.data.gapminder().query("country=='Canada'")
      fig = px.line(
          df, x="year", y="lifeExp", title="Life expectancy in Canada"
      )
      st.plotly_chart(fig, theme=theme_value)
  
      el = self.get_delta_from_queue().new_element
      self.assertEqual(el.plotly_chart.theme, proto_value)
  
file_path: streamlit/lib/tests/streamlit/elements/plotly_chart_test.py
imports: from unittest import mock
  import plotly.express
  from parameterized import parameterized
  import streamlit
  from streamlit.errors import StreamlitAPIException
  from tests.delta_generator_test_case import DeltaGeneratorTestCase
label_desc: Use image node_id 2 for calling the PyDeckTest obj's underlying member method code with example usage: obj.test_theme(theme_value, proto_value) without return types