Package validator sets up several methods for simple validation as well as setting up an interface which when implemented allows for custom validation logic by the implementor. `Valid()` returns a boolean indicating if the value(s) passed into it are valid based on the different types. `Assert()` returns an error indicating `nil` if the values are valid. Otherwise `Assert()` returns an error indicating the index of the value(s) passed into it as to which was determined to be invalid.