Insert ... if doesn't exist - into cassandra trigger

I am learning about using cassandra trigger to insert into multiple tables when inserting into a table.

So, there is one table where I would like to use

insert into tbl (...) values(...) if not exists;

      

        
        
        
      

    

I would like to know how to apply this, if no logic exists, to the RowMutation in ITrigger. Is it possible?