code: def f3(x):
      r"""A quartic with roots at 0, 1, 2 and 3"""
      return x * (x - 1.0) * (x - 2.0) * (x - 3.0)
  
imports: from __future__ import division, print_function, absolute_import
  from random import random
  import numpy
  from scipy.optimize import zeros
label_desc: Use image node_id 7 for calling a global function with example usage: f3(x) and returns: unknown