input: from typing import List
  
  def delete_item_from_list(items: List[str], item_to_delete: str) -> str:
      """ Deletes a specified item from a list and returns a message indicating the result.
      >>> delete_item_from_list(["Apple", "Banana", "Orange"], "Banana")
      "Item successfully deleted."
      >>> delete_item_from_list(["Apple", "Banana", "Orange"], "Grape")
      "Item not found."
      """
output:     if item_to_delete in items:
          items.remove(item_to_delete)
          return "Item successfully deleted."
      else:
          return "Item not found."