I just want to append some additional comment, you can leave it. My opinion is, this kind of monkey patching can increase the debugging time in the future, because the new developer won't know where ```polish_or_swiss?``` is defined on the string (especially if you start to use this method in another component that depends on this) and it can be misleading. I prefer monkey patching when it adds an additional feature to the specified class, here for String, like ```empty?```. IMO string can't be polish or swiss, a special object can be, like PainNumber, or SEPA, and this class should have ```polish_or_swiss?``` method.