I believe the Shakespeare url needs to be changed to the following: https://www.gutenberg.org/cache/epub/1513/pg1513.txt

the listed url for romeo and juliet has a 404 error:
Read this url and find the 10 most frequent words. romeo_and_juliet = 'http://www.gutenberg.org/files/1112/1112.txt'

Looks like there is an error in the rest countries api url as well (returns not found)

I think you may be looking for this url: https://restcountries.com/v3.1/all?fields=name,capital,currencies