code: def test_make_params_empty(self):
      params = utils.make_params(foo=None, bar=None)
      self.assertEqual(params, {})
  
imports: from __future__ import absolute_import
  import json
  from requests.exceptions import ConnectionError
  from plotly import version
  from chart_studio.api.utils import to_native_utf8_string
  from chart_studio.api.v2 import utils
  from chart_studio.exceptions import PlotlyRequestError
  from chart_studio.session import sign_in
  from chart_studio.tests.test_plot_ly.test_api import PlotlyApiTestCase
label_desc: Use image node_id 2 for calling the MakeParamsTest obj's underlying member method code with example usage: obj.test_make_params_empty() without return types