input: Write a python function to analyze the sentiment of a given sentence using TextBlob.
  assert identify_sentiment('I love this product, it is amazing!') > 0
  assert identify_sentiment('I am not sure about the quality of this item.') == 0
  assert identify_sentiment('This is the worst experience I have ever had.') < 0
output: def identify_sentiment(sentence):
      from textblob import TextBlob
      blob = TextBlob(sentence)
      return blob.sentiment.polarity