Write code to assign the number of characters in the string rv to a variable num_chars. Save & Run Load History Show CodeLens 2 3 1 rv = "*"Once upon a midnight dreary, while I pondered, weak and weary, Over many a quaint and curious volume of forgotten lore, While I nodded, nearly napping, suddenly there came a tapping, As of some one gently rapping, rapping at my chamber door. 'Tis some visitor, I muttered, tapping at my chamber door; 6 Only this and nothing more."" 8 # Write your code here! 9 10