L7 : OPTIONAL argument keyword usage

Optional arguments passed to a routine shall have their keyword specified.

To be avoided :

OPTIONAL argument keyword

!! interface of OPT_ARG subroutine is below
CALL OPT_ARG( IVAL1,IVAL2,IVAL3)


SUBROUTINE OPT_ARG( ARG1, ARG2, ARG3)

INTEGER(KIND=JPIM), INTENT(IN)          :: ARG1
INTEGER(KIND=JPIM), INTENT(OUT)         :: ARG2
INTEGER(KIND=JPIM), INTENT(IN),OPTIONAL :: ARG3