def get_yes_no_input(prompt_message):
    """
    Prompts the user for a yes/no input and returns True for yes, False for no.
    Handles variations like 'y', 'yes', 'n', 'no' (case-insensitive).
    """
    while True:
        user_input = input(f"{prompt_message} (yes/no): ").lower().strip()      # conver to lower case and remove trailing white spaces.
        if user_input in ('yes', 'y'):
            return True
        elif user_input in ('no', 'n'):
            return False
        else:
            print("Invalid input. Please enter 'yes' or 'no'.")

# Example usage:
if get_yes_no_input("Do you want to continue?"):
    print("Good. Here is another question.")
else:
    print("User chose to stop.")

answer = get_yes_no_input("Is life a box of chocolate?")
if answer:
    print("Great!")
else:
    print("Then, get pizza.")