code: def tokenize(s, eos=True):
      s = clean_string(s)
      if eos and len(s) > 0:
          return (s + " <eos>").strip().split()
      else:
          return s.strip().split()
  
imports: import os
  import numpy
  from collections import defaultdict, OrderedDict
  from neon.layers import LookupTable, RecurrentSum, RecurrentLast, Linear, Bias, GeneralizedCost
  from neon.initializers import Gaussian, Constant
  from neon.data import ArrayIterator
  from neon.data.text_preprocessing import clean_string
  from neon.optimizers import GradientDescentMomentum
  from neon.transforms import SumSquared
  from neon.callbacks.callbacks import Callbacks
  from neon.models import Model
  from neon.util.persist import load_obj, save_obj
  from neon import logger
label_desc: Use image node_id 2 for calling a global function with example usage: tokenize(s, eos) and returns: unknown, s