Product20 is a Cartesian product of 20 components.
Returns the n-th projection of this product if 0 <= n < productArity,
otherwise throws an
A method that should be called from every well-designed equals method that is open to be overridden in a subclass. See Programming in Scala, Chapter 28 for discussion and design.
The name of the nth element of this product, 0-based. In the default implementation, an empty string.