input: Write a function to analyze the sentiment of given text and categorize it into positive, negative, and neutral sentiments. If the given text has more negative sentences than positive, return 'negative'. If the given text has more positive sentences than negative, return 'positive'. If the number of positive and negative sentences is equal, return 'neutral'. If the given text is empty then return 'neutral'.
  assert analyze_sentiment("I am happy. I am sad.") == 'neutral'
  assert analyze_sentiment("This is a bad day. This is a good day.") == 'neutral'
  assert analyze_sentiment("I hate this. I love this.") == 'neutral'
  assert analyze_sentiment("Everything is terrible.") == 'negative'
  assert analyze_sentiment("Everything is wonderful.") == 'positive'
  assert analyze_sentiment("") == 'neutral'
output: def analyze_sentiment(text):
      if not text:
          return 'neutral'
      
      sentences = text.split('.')
      positive_count = 0
      negative_count = 0
      
      for sentence in sentences:
          if 'happy' in sentence or 'good' in sentence or 'love' in sentence or 'wonderful' in sentence:
              positive_count += 1
          if 'sad' in sentence or 'bad' in sentence or 'hate' in sentence or 'terrible' in sentence:
              negative_count += 1
      
      if positive_count > negative_count:
          return 'positive'
      elif negative_count > positive_count:
          return 'negative'
      else:
          return 'neutral'