code: def test_contour_legend_elements():
      x = np.arange(1, 10)
      y = x.reshape(-1, 1)
      h = x * y
  
      colors = ["blue", "#00FF00", "red"]
      cs = plt.contour(
          h, levels=[10, 30, 50], colors=colors, extend="both"
      )
      artists, labels = cs.legend_elements()
      assert labels == ["$x = 10.0$", "$x = 30.0$", "$x = 50.0$"]
      assert all(isinstance(a, mpl.lines.Line2D) for a in artists)
      assert all(
          same_color(a.get_color(), c) for a, c in zip(artists, colors)
      )
  
imports: import datetime
  import platform
  import re
  from unittest import mock
  import contourpy
  import numpy
  from numpy.testing import assert_array_almost_equal, assert_array_almost_equal_nulp, assert_array_equal
  import matplotlib
  from matplotlib import pyplot, rc_context, ticker
  from matplotlib.colors import LogNorm, same_color
  import matplotlib.patches
  from matplotlib.testing.decorators import check_figures_equal, image_comparison
  import pytest
label_desc: Use image node_id 35 for calling a global function with example usage: test_contour_legend_elements() without return types