returns a function that can be used to instantiate the class using a no-arg constructor
returns a function that can be used to instantiate the class using 1 arg constructor
returns a function that can be used to instantiate the class using 2 arg constructor
returns a function that can be used to instantiate the class using 3 arg constructor
returns a function that can be used to instantiate the class using 3 arg constructor
provides easy access to instance construction