These options will be used on objects of class 'S7_generic'.
opts_S7_generic(constructor = c("new_generic", "next"), ...)An object of class <constructive_options/constructive_options_S7_generic>
Depending on constructor, we construct the object as follows:
"new_generic" (default): We build the object using S7::new_generic().
"next" : Use the constructor for the next supported class.