code: def explicit_fjd(self, B, x):
      eBx = np.exp(B[2] * x)
      ret = B[1] * 2.0 * (eBx - 1.0) * B[2] * eBx
      return ret
  
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 5 for calling the TestODR obj's underlying member method code with example usage: obj.explicit_fjd(B, x) and returns: ret