input: Write a python function to find the most frequent words in a given text using collections.Counter.
  assert find_frequent_words("This is a sentence. This sentence is just a sentence.") == [('This', 2), ('is', 2), ('a', 2), ('sentence.', 2), ('sentence', 1), ('just', 1)]
  assert find_frequent_words("Hello world! Hello everyone. This is a test.") == [('Hello', 2), ('world!', 1), ('everyone.', 1), ('This', 1), ('is', 1), ('a', 1), ('test.', 1)]
  assert find_frequent_words("Python code. Code in Python. Write Python code.") == [('Python', 3), ('code.', 2), ('Code', 1), ('in', 1), ('Write', 1)]
output: def find_frequent_words(text):
      from collections import Counter
      words = text.split()
      word_count = Counter(words)
      return word_count.most_common()