code: def test_validate_2D_density(self):
      # validate that x and y contain only numbers
      x = [1, 2]
      y = ["a", 2]
  
      pattern = (
          "All elements of your 'x' and 'y' lists must be numbers."
      )
  
      self.assertRaisesRegex(
          PlotlyError, pattern, ff.create_2d_density, x, y
      )
  
      # validate that x and y are the same length
      x2 = [1]
      y2 = [1, 2]
  
      pattern2 = "Both lists 'x' and 'y' must be the same length."
  
      self.assertRaisesRegex(
          PlotlyError, pattern2, ff.create_2d_density, x2, y2
      )
  
imports: import math
  from unittest import TestCase
  import datetime
  import plotly.figure_factory
  import plotly.io
  from plotly.exceptions import PlotlyError
  from plotly.tests.test_optional.optional_utils import NumpyTestUtilsMixin
  from plotly.graph_objs import graph_objs
  from plotly.tests.utils import TestCaseNoTemplate
label_desc: Use image node_id 1 for calling the Test2D_Density obj's underlying member method code with example usage: obj.test_validate_2D_density() without return types