input: from collections import Counter
  
  
  def generate_ngrams(text, window_size):
      """ Generate n-grams of the given text with a specified window size.
      >>> generate_ngrams("The quick brown fox jumps over the lazy dog", 3)
      Counter({'the quick brown': 3, 
               'quick brown fox': 2, 
               'over the lazy': 1, 
               'brown fox jumps': 1, 
               'fox jumps over': 1, 
               'the lazy dog': 1, 
               'jumps over the': 1, 
               'quick brown fox jumps': 1})
      """
      text = text.lower().split(' ')
      ngrams = []
      for n in range(window_size, len(text)+1):
          for i in range(len(text)-n+1):
              ngrams.append(' '.join(text[i:i+n]))
      return Counter(ngrams)
output:     text = text.lower().split(' ')
      ngrams = []
      for n in range(window_size, len(text)+1):
          for i in range(len(text)-n+1):
              ngrams.append(' '.join(text[i:i+n]))
      return Counter(ngrams)