In the samples I believe there's an error. It says:

get_textliterals("'this' is sample 'too'") -> [(0, 6), (15, 20)]

But it should be:

get_textliterals("'this' is sample 'too'") -> [(0, 6), (17, 22)]

• needs random tests
• the code sent to the user with test6 seems incorrect to me: the string should be stripped from its last line feed character (or he specs for "adding a ' to close the litterals" has to be more... specific)