input: Write a python function to detect sentiment of a given text.
  assert detect_sentiment("I love this!") == 'positive'
  assert detect_sentiment("This is okay.") == 'neutral'
  assert detect_sentiment("I hate this.") == 'negative'
output: def detect_sentiment(text):
      from textblob import TextBlob
      
      analysis = TextBlob(text)
      polarity = analysis.sentiment.polarity
      
      if polarity > 0:
          return 'positive'
      elif polarity == 0:
          return 'neutral'
      else:
          return 'negative'