input: Write a function to calculate the total cost of a shopping cart, considering the item prices, quantity, shipping cost, and any applicable taxes. The function should return the total cost as a float. If the shopping cart is empty, the function should return 0.
  assert calculate_total_cost([{"name": "widget", "price": 10, "quantity": 5}, {"name": "thingy", "price": 7, "quantity": 3}, {"name": "doodad", "price": 5, "quantity": 2}], 7.50, 0.095) == 98.6875
  assert calculate_total_cost([{"name": "gadget", "price": 20, "quantity": 1}], 5.00, 0.08) == 26.6
  assert calculate_total_cost([], 0, 0) == 0
output: def calculate_total_cost(cart, shipping_cost, tax_rate):
      if not cart:
          return 0
      subtotal = sum(item['price'] * item['quantity'] for item in cart)
      total_cost = subtotal + shipping_cost
      total_cost += total_cost * tax_rate
      return total_cost