Preventing a Function from Modifying a List (function_name(list_name[:])) from Python Crash Course gave me an syntax error

This is the original code that works:

def printed_models(unprinted_designs,completed_models):
    while unprinted_designs:
        current_design= unprinted_designs.pop()
        print(f"Printing model: {current_design}")
        completed_models.append(current_design)
def show_completed_models(completed_models):
    print("\nThe following models have been printed:")
    for completed_model in completed_models:
        print(completed_model)
unprinted_designs=['robot','rocket','terminator']
completed_models=[]        
printed_models(unprinted_designs,completed_models)
show_completed_models(completed_models)

This is the code after adding [:] for unprinted_designs to keep the original list as the book shows. It gave me an syntax error after I added [:]

def print_models(unprinted_designs[:], completed_models):
    while unprinted_designs:
        current_design= unprinted_designs.pop()
        print(f"Printing model: {current_design}")
        completed_models.append(current_design)
def show_completed_models(completed_models):
    print("\nThe following models have been printed:")
    for completed_model in completed_models:
        print(completed_model)
unprinted_designs=['robot','rocket','terminator']
completed_models=[]        
printed_models(unprinted_designs,completed_models)
show_completed_models(completed_models)