input: Write a python function to count the frequency of each word in a given text.
  assert wordcount("hello world hello") == {'hello': 2, 'world': 1}
  assert wordcount("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 wordcount("test test test case case") == {'test': 3, 'case': 2}
output: def wordcount(text):
      words = text.split()
      word_freq = {}
      for word in words:
          if word in word_freq:
              word_freq[word] += 1
          else:
              word_freq[word] = 1
      return word_freq