input: Write a function to classify the sentiment of movie reviews using Natural Language Processing. The function should return the sentiment as either "negative" or "positive" based on the input sentence. If the negative score is higher than the positive score, the sentiment should be classified as "negative". Otherwise, it should be classified as "positive".
  assert classify_sentiment("The movie was terrible. It felt like it would never end!")=='negative'
  assert classify_sentiment("The movie was fantastic! I loved every minute of it.")=='positive'
  assert classify_sentiment("The movie was average.")=='positive'  # Since the negative score is not higher
  assert classify_sentiment("The worst movie I have ever seen.")=='negative'
  assert classify_sentiment("")=='positive'  # Empty string default to positive
output: def classify_sentiment(sentence):
      from textblob import TextBlob
      blob = TextBlob(sentence)
      sentiment = blob.sentiment
      if sentiment.polarity < 0:
          return 'negative'
      else:
          return 'positive'