you can not see the conversion from String to integer, because it is a class method : DALCountry .
DAL , stands for: Data Access Layer .
The conversion of " countryname " to integer data type , can be given in different ways, but the most is roughly a query to the database : "SELECT ID FROM WHERE CountryName Country = 'USA'"
With the above query, an identifier is obtained for countryName
And that outcome , which will return the function CreateCountry
And I hope it helped you on your question
Best regards From Mexico.