input: Write a function to get customer names from a given dictionary.
  assert get_customer_names({1: {"name": "John", "email": "john@example.com"}}) == ["John"]
  assert get_customer_names({
    1: {"name": "John", "email": "john@example.com"},
    2: {"name": "Jane", "email": "jane@example.com"}
  }) == ["John", "Jane"]
  assert get_customer_names({}) == []
output: def get_customer_names(customers):
      return [info["name"] for info in customers.values()]