# File lib/pluginfactory.rb, line 124
124:         def self::extend_object( obj )
125:                 unless obj.is_a?( Class )
126:                         raise TypeError, "Cannot extend a #{obj.class.name}", caller(1)
127:                 end
128:                 obj.instance_variable_set( :@derivatives, {} )
129:                 super
130:         end