input: Write a python function to count the occurrences of words with length greater than or equal to 3 using defaultdict.
  assert count_words('The quick brown fox jumps over the lazy dog. The fox barked at the dog.') == {'The': 2, 'quick': 1, 'brown': 1, 'fox': 2, 'jumps': 1, 'over': 1, 'the': 1, 'lazy': 1, 'dog.': 1, 'barked': 1, 'dog.': 1}
  assert count_words('This is a test. This test is only a test.') == {'This': 2, 'test.': 2, 'only': 1, 'test.': 1}
  assert count_words('Python is fun! Python is powerful.') == {'Python': 2, 'fun!': 1, 'powerful.': 1}
output: from collections import defaultdict
  import re
  
  def count_words(text):
      word_counts = defaultdict(int)
      words = re.findall(r'\b\w+\b', text)
      for word in words:
          if len(word) >= 3:
              word_counts[word] += 1
      return dict(word_counts)