code: def test_set_default_template(self):
      orig_default = pio.templates.default
      pio.templates.default = "plotly"
      fig = go.Figure()
      self.assertEqual(
          fig.layout.template.to_plotly_json(),
          pio.templates["plotly"].to_plotly_json(),
      )
      pio.templates.default = orig_default
  
imports: import copy
  from unittest import TestCase
  import pytest
  import plotly.io
  import plotly.graph_objs
  from plotly.tests.utils import TestCaseNoTemplate
label_desc: Use image node_id 9 for calling the TestMergeTemplates obj's underlying member method code with example usage: obj.test_set_default_template() without return types