input: Write a python function to calculate the total cost from a list of orders where each order is a dictionary containing a 'price' key.
  assert calculate_total_cost([{'price': 10}, {'price': 20}, {'price': 30}]) == 60
  assert calculate_total_cost([{'price': 5.5}, {'price': 12.75}, {'price': 8.25}]) == 26.5
  assert calculate_total_cost([]) == 0
output: def calculate_total_cost(orders):
      return sum(order['price'] for order in orders)