input: Write a python function to count the occurrences of each item in a list.
  assert count_items(['apple', 'banana', 'apple', 'orange', 'banana', 'apple']) == {'apple': 3, 'banana': 2, 'orange': 1}
  assert count_items([1, 2, 2, 3, 3, 3, 4]) == {1: 1, 2: 2, 3: 3, 4: 1}
  assert count_items([]) == {}
output: def count_items(items):
      counts = {}
      for item in items:
          if item in counts:
              counts[item] += 1
          else:
              counts[item] = 1
      return counts