input: Write a python function to count the occurrences of each word in a list.
  assert word_count(['a', 'b', 'a', 'a', 'c', 'b', 'd', 'a']) == {'a': 4, 'b': 2, 'c': 1, 'd': 1}
  assert word_count(['apple', 'banana', 'apple', 'orange', 'banana', 'apple']) == {'apple': 3, 'banana': 2, 'orange': 1}
  assert word_count([]) == {}
output: def word_count(words):
      count_dict = {}
      for word in words:
          if word in count_dict:
              count_dict[word] += 1
          else:
              count_dict[word] = 1
      return count_dict