code: def empty_data_func(self, B, x):
      return B[0] * x + B[1]
  
imports: from __future__ import division, print_function, absolute_import
  import numpy
  from numpy import pi
  from numpy.testing import assert_array_almost_equal, assert_equal, assert_warns
  from pytest import raises
  from scipy.odr import Data, Model, ODR, RealData, OdrStop, OdrWarning
label_desc: Use image node_id 2 for calling the TestODR obj's underlying member method code with example usage: obj.empty_data_func(B, x) and returns: unknown