input: Write a python function to calculate the sentiment polarity score of a given text using TextBlob.
  assert sentiment_score("This movie was an amazing experience!") == 0.9
  assert sentiment_score("The food was terrible and service was bad.") == -0.85
  assert sentiment_score("It was an average day, nothing special.") == 0.0
output: def sentiment_score(text):
      from textblob import TextBlob
      return TextBlob(text).sentiment.polarity