code: def test_nested_update_underscores(self):
      assert self.scatter["error_x.type"] is None
      self.scatter.update({"error_x_type": "percent"})
  
      assert self.scatter["error_x_type"] == "percent"
      d1, d2 = strip_dict_params(
          self.scatter, self.expected_nested_error_x
      )
      assert d1 == d2
  
imports: from unittest import TestCase
  import plotly.graph_objs
  from plotly.tests.utils import strip_dict_params
label_desc: Use image node_id 10 for calling the TestAssignmentPrimitive obj's underlying member method code with example usage: obj.test_nested_update_underscores() without return types