code: def eg_cmaps():
      E = SimpleNamespace()
  
      def f(x):
          return 2 * x
  
      def g(x):
          return x / 2.0
  
      x = CoordinateSystem("x", "x")
      E.a = CoordinateMap(x, x, f)
      E.b = CoordinateMap(x, x, f, inverse_function=g)
      E.c = CoordinateMap(x, x, g)
      E.d = CoordinateMap(x, x, g, inverse_function=f)
      E.e = AffineTransform.identity("ijk")
      A = np.identity(4)
      A[0:3] = np.random.standard_normal((3, 4))
      E.mapping = AffineTransform.from_params("ijk", "xyz", A)
      E.singular = AffineTransform.from_params(
          "ijk",
          "xyzt",
          np.array(
              [
                  [0, 1, 2, 3],
                  [4, 5, 6, 7],
                  [8, 9, 10, 11],
                  [8, 9, 10, 11],
                  [0, 0, 0, 1],
              ]
          ),
      )
      return E
  
imports: from copy import copy
  from types import SimpleNamespace
  import numpy
  from ..coordinate_map import AffineTransform, AxisError, CoordinateMap, CoordMapMaker, CoordMapMakerError, _as_coordinate_map, _fix0, append_io_dim, axmap, compose, drop_io_dim, equivalent, input_axis_index, io_axis_indices, orth_axes, product, shifted_domain_origin, shifted_range_origin
  from ..coordinate_system import CoordinateSystem, CoordinateSystemError, CoordSysMaker
  import pytest
  from numpy.testing import assert_almost_equal, assert_array_equal
label_desc: Use image node_id 1 for calling a global function with example usage: eg_cmaps() and returns: E, unknown, unknown