Don't change subclass results to superclass.
Don't change subclass results to superclass.

NB: I use self.class.new here rather than Table.new because if this class is
inherited, I want the result to be an instance of the subclass.  With
Table.new, this method's result will be an instance of FatTable::Table rather
than of the subclass.

ddoherty03/fat_table,ddoherty03/fat_table