code: def test_exponential_model(self):
      x = np.linspace(0.0, 5.0)
      y = -10.0 + np.exp(0.5 * x)
      data = Data(x, y)
      odr_obj = ODR(data, exponential)
      output = odr_obj.run()
      assert_array_almost_equal(output.beta, [-10.0, 0.5])
  
imports: import tempfile
  import shutil
  import os
  import numpy
  from numpy import pi
  from numpy.testing import assert_array_almost_equal, assert_equal, assert_warns
  import pytest
  from pytest import raises
  from scipy.odr import Data, Model, ODR, RealData, OdrStop, OdrWarning, multilinear, exponential, unilinear, quadratic, polynomial
label_desc: Use image node_id 20 for calling the TestODR obj's underlying member method code with example usage: obj.test_exponential_model() without return types