What does the question mark at the end of a method name mean in Ruby?
ruby
Solution
It is a code style convention; it indicates that a method returns a boolean value (true or false) or an object to indicate a true value (or “truthy” value).
The question mark is a valid character at the end of a method name.
https://docs.ruby-lang.org/en/2.0.0/syntax/methods_rdoc.html#label-Method+Names
Problem
What is the purpose of the question mark operator in Ruby? Sometimes it appears like this: ``` assert !product.valid? ``` sometimes it's in an `if` construct.