input: Write a python function to find the most popular item from a list of dictionaries.
  assert most_popular_item([{'name': 'apple', 'count': 10}, {'name': 'banana', 'count': 15}, {'name': 'orange', 'count': 7}]) == 'banana'
  assert most_popular_item([{'name': 'pen', 'count': 5}, {'name': 'pencil', 'count': 12}, {'name': 'eraser', 'count': 8}]) == 'pencil'
  assert most_popular_item([{'name': 'chair', 'count': 3}, {'name': 'table', 'count': 2}, {'name': 'lamp', 'count': 3}]) == 'chair'
output: def most_popular_item(items):
      return max(items, key=lambda x: x['count'])['name']