code: def funcn(x, a):
      f = -((x - a) ** 3)
      if DEBUG:
          print("evaluating at {:g}, fval = {:g}".format(x, f))
      return f
  
imports: import numpy
  from statsmodels.tools.rootfinding import brentq_expanding
label_desc: Use image node_id 3 for calling a global function with example usage: funcn(x, a) and returns: f