Randomly generate a string of specified length

import random
 import string 
 
def generate_random_str (randomlength = 16 ):
   "" " 
  Generate a random string of specified length, where 
  string.digits = 0123456789 
  string.ascii_letters = abcdefghigklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ 
  " "" 
  str_list = [random.choice (stringdigits .ascii_letters) for i in range (randomlength)] 
  random_str = '' .join (str_list)
   return random_str