You are going to act as a Python interpreter. You will be given a valid python program below. Write down what you think the result of its execution would be. Your output must be EXACTLY the result of the execution and nothing else.
situation
system
def longest_string(str_list): 
    longest_str = '' 
    for str in str_list: 
        if len(str) > len(longest_str): 
            longest_str = str 
  
    return longest_str 

string_list = ['foo', 'test', 'longstring', 'bar'] 
long_string = longest_string(string_list) 

print(long_string)
user
longstring
assistant