- Checker
A function which takes an input value and indicates (
True/False) whether it contains what you expect. Will always return a Boolean value, and will not raise an exception on failure.- Validator
A function which takes an input value and ensures that it is what (the type or contents) you expect it to be. Will return the value or
None <python:None>depending on the arguments you pass to it, and will raise an exception if validation fails.