Because the sorting closure is passed as an argument to a function, Swift can infer the
types of its parameters and the type of the value it returns from the type of the sort
function’s second parameter. This parameter is expecting a function of type (String, String) ->
Bool. This means that the String, String, and Bool types do not need to be written as part of the
closure expression’s definition. Because all of the types can be inferred, the return arrow
(->) and the parentheses around the names of the parameters can also be omitted: