code: def funcn(x, a):
      f = -((x - a) ** 3)
      return f
  
imports: import numpy
  from statsmodels.tools.rootfinding import brentq_expanding
  from numpy.testing import assert_allclose, assert_equal, assert_raises, assert_array_less
label_desc: Use image node_id 3 for calling a global function with example usage: funcn(x, a) and returns: f