How to define this type in this code

Hi all.

I am trying to make a program work , but got stuck  on how to define this type : "zmsg_type"

REPORT  myProgram.

PARAMETERS :p_all TYPE zmsg_typeAS LISTBOX VISIBLE LENGTH 10

                                                    USER-COMMAND us1,   " Message type

                           p_email TYPE   ad_smtpadr     MODIF ID md2,
                          p_print  TYPE   tsp03-padest   MODIF ID md3.

TYPES : BEGIN OF lty_all,
                all TYPE zmsg_type,
              END OF lty_all.

Thank you very much.