[$] A literal string type for Python

Using strings with contents that are supplied by users can be fraught withperil; SQL injection is a well-known technique for attacking applicationsthat stems from that, for example. Generally, database frameworks andlibraries provide mechanisms that seek to lead programmers toward doing TheRight Thing, with parameterized queries and the like, but they cannotenforce that-inventive developers will seemingly always find ways to injectuser input into places it should not go. A recently adopted PythonEnhancement Proposal (PEP) provides a way to enforce the use of strings that are untainted by user input, but it uses the optional typing featuresof the language to do so; those wanting to take advantage of it will needto be running a type-checking program.