input: Write a function that takes in a text string and returns a dictionary of words and the number of times each word appears in the text string. If the text string is empty, return an empty dictionary.
  
  def count_word_freq(text):
   if not text:
   return {}
   word_freq = {}
   for word in text.split():
   if word in word_freq:
   word_freq[word] += 1
   else:
   word_freq[word] = 1
   return word_freq
  
  assert count_word_freq("A quick brown fox jumps over the lazy dog")=={'A': 1, 'quick': 1, 'brown': 1, 'fox': 1, 'jumps': 1, 'over': 1, 'the': 1, 'lazy': 1, 'dog': 1}
  assert count_word_freq("the quick the brown quick fox")=={'the': 2, 'quick': 2, 'brown': 1, 'fox': 1}
  assert count_word_freq("")=={}
output: def count_word_freq(text):
      if not text:
          return {}
      word_freq = {}
      for word in text.split():
          if word in word_freq:
              word_freq[word] += 1
          else:
              word_freq[word] = 1
      return word_freq