input: Write a python function to calculate the total amount from a list of dictionaries.
  assert calculate_total([{'name': 'item1', 'amount': 10}, {'name': 'item2', 'amount': 20}, {'name': 'item3', 'amount': 30}]) == 60
  assert calculate_total([{'name': 'item1', 'amount': 15}, {'name': 'item2', 'amount': 25}, {'name': 'item3', 'amount': 35}]) == 75
  assert calculate_total([{'name': 'item1', 'amount': 0}, {'name': 'item2', 'amount': 0}, {'name': 'item3', 'amount': 0}]) == 0
output: def calculate_total(items):
      return sum(item['amount'] for item in items)