Backticks should be ignored in variable name as referred in https://developer.apple.com/library/content/documentation/Swift/Conceptual/Swift_Programming_Language/LexicalStructure.html

To use a reserved word as an identifier, put a backtick () before and after it. For example, class is not a valid identifier, but classis valid. The backticks are not considered part of the identifier;x` and x have the same meaning.