this method is the basic structure for performing a job in the AbstractAction structure,But Here we needed more
simple structure ;so we defined GraphAction and so there was no need of this signature!
each plugin can have a class that implements this interface,
the implementing class will have the methods that are implemented
in various parts of the plugin, they will be easily accessed by other
parts of program,
it is probable that useful tools created to work with this objects, and
automaize some processes of creating plugins, so we suggest that implement
this interface in your plugins,,, :D