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 input list of items is empty, return 0.0.
  
  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) == 97.525
  
  assert calculate_total_cost([ 
   {"name": "widget", "price": 10, "quantity": 1 },
   {"name": "thingy", "price": 7, "quantity": 1 },
  ], 5.0, 0.10) == 25.7
  
  assert calculate_total_cost([], 0.0, 0.0) == 0.0
  
  assert calculate_total_cost([ 
   {"name": "widget", "price": 1, "quantity": 10 },
  ], 2.0, 0.05) == 12.5
output: def calculate_total_cost(items, shipping_cost, tax_rate):
      if not items:
          return 0.0
      subtotal = sum(item["price"] * item["quantity"] for item in items)
      total_cost = subtotal + shipping_cost
      total_cost += total_cost * tax_rate
      return total_cost