input: Write a python function to count the frequency of each word in a given string.
  assert count_word_frequency("A few words, some more words!") == {'A': 1, 'few': 1, 'words,': 1, 'some': 1, 'more': 1, 'words!': 1}
  assert count_word_frequency("Hello world Hello") == {'Hello': 2, 'world': 1}
  assert count_word_frequency("Test test test") == {'Test': 1, 'test': 2}
output: def count_word_frequency(s):
      words = s.split()
      frequency = {}
      for word in words:
          if word in frequency:
              frequency[word] += 1
          else:
              frequency[word] = 1
      return frequency