I may just not be understanding the README but I'm finding that `isValidPhoneNumber` does not correctly use the country code for validation. For example: ``` isValidPhoneNumber('+524779800413', 'US') # => true ``` This is saying the phone number is a valid US phone number but it is a Mexican number. Is this expected? If so, can you elaborate what it means in the README where it says "`isValidPhoneNumber()` validates both phone number length and the actual phone number digits.". What is it validating about the digits? I did find an undocumented method, `isValidNumberForRegion` which seems to correctly validate a phone belongs to a region. ``` isValidNumberForRegion('+524779800413', 'US') # => false isValidNumberForRegion('+16145134567', 'US') # => true ``` Is it ok to use this method? Google's library is giving the same result so I understand this is not a bug, but just wanted to be clear on what digit validation is being performed by `isValidPhoneNumber` to know which I should use for my use case. Demo Page https://catamphetamine.gitlab.io/libphonenumber-js/?parseCountry=US&parseValue=%2B524779800413&asYouTypeCountry=US&findNumbersCountry=US&findNumbersText=For%20more%20details%20call%20%2B7%20(800)%20555-35-35%20internationally%20or%20reach%20the%20local%20US%20branch%20at%20(213)%20373-4253%20ext.%201234%20for%20paid%20customer%20support. Google Demo Page https://libphonenumber.appspot.com/phonenumberparser?number=%2B524779800413&country=US