text: import os
  import argparse
  import numpy as np
  
  def filter_non(data):
      data = data[data.Review.notnull()]
  
      if 'Sentiment' in data.columns:
          data = data[data.Sentiment.notnull()]
          data["Label"] = data["Sentiment"].apply(lambda l: int(l == 'Positive'))
  
      return data
  
  # remove words which length less than 2
  def preprocess(sentence) :
      words_clean = [w.lower() for w in sentence.split() if len(w) >= 3]
      words_clean = [ w for w in words_clean if not w.isdigit() ]
      return words_clean