input: Write a python function to calculate the total cost of items in a list where each item is represented by a sublist containing the item name, quantity, and price per unit.
  assert calculate_total_cost([['Item 1', 2, 3.00], ['Item 2', 5, 1.50]]) == 12.50
  assert calculate_total_cost([['Item A', 1, 10.00], ['Item B', 2, 7.50], ['Item C', 3, 4.00]]) == 39.00
  assert calculate_total_cost([['Product 1', 3, 5.00], ['Product 2', 4, 2.50]]) == 27.50
output: def calculate_total_cost(items):
      total_cost = 0
      for item in items:
          name, quantity, price_per_unit = item
          total_cost += quantity * price_per_unit
      return total_cost