input: Write a function to generate n-grams of the given text with a specified window size. The function should return a Counter object containing the n-grams and their counts.
  
  
  from collections import Counter
  
  def generate_ngrams(text, window_size):
      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)
  
  assert generate_ngrams("The quick brown fox jumps over the lazy dog", 3) == \
         Counter({'the quick brown': 1, 'quick brown fox': 1, 'brown fox jumps': 1, 'fox jumps over': 1, 'jumps over the': 1, 'over the lazy': 1, 'the lazy dog': 1, 'the quick brown fox': 1, 'quick brown fox jumps': 1, 'brown fox jumps over': 1, 'fox jumps over the': 1, 'jumps over the lazy': 1, 'over the lazy dog': 1})
  assert generate_ngrams("This is a test", 2) == \
         Counter({'this is': 1, 'is a': 1, 'a test': 1, 'this is a': 1, 'is a test': 1})
  assert generate_ngrams("Hello", 1) == \
         Counter({'hello': 1})
  assert generate_ngrams("", 3) == \
         Counter()
  assert generate_ngrams("A A A A", 1) == \
         Counter({'a': 4})
  
output: 
  def generate_ngrams(text, window_size):
      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)
  