code: def test_function_scale():
      def inverse(x):
          return x**2
  
      def forward(x):
          return x ** (1 / 2)
  
      fig, ax = plt.subplots()
  
      x = np.arange(1, 1000)
  
      ax.plot(x, x)
      ax.set_xscale("function", functions=(forward, inverse))
      ax.set_xlim(1, 1000)
  
imports: import copy
  import matplotlib.pyplot
  from matplotlib.scale import AsinhScale, AsinhTransform, LogTransform, InvertedLogTransform, SymmetricalLogTransform
  import matplotlib.scale
  from matplotlib.ticker import AsinhLocator, LogFormatterSciNotation
  from matplotlib.testing.decorators import check_figures_equal, image_comparison
  import numpy
  from numpy.testing import assert_allclose
  import io
  import pytest
label_desc: Use image node_id 12 for calling a global function with example usage: test_function_scale() and returns: unknown, unknown