code: def _get_args(self, executable, *args):
          
          args = list(args)
          args.insert(0, executable)
          if self.username:
              args.append("--username={}".format(self.username))
          if self.host:
              args.append("--host={}".format(self.host))
          if self.port:
              args.append("--port={}".format(self.port))
  
          args.append(self.dbname)
          #args.extend(other_args)
          return args
docs: compile all the executable and the arguments, combining with common arguments
          to create a full batch of command args