Error type y0bs_Dev is unknown in read_text and save_text FM.

Hello all i am using a container and want to save its text by se75 (text object and ID)

by using a FM of read text and save text I am getting this error type y0bs_dev is unknown below is the code which i am using . Also tell me is this code correct?

FORM get_comments

USING p_Devobjid TYPE y0bs_Dev-objid.

DATA: e_header TYPE thead.

DATA: i_tline TYPE STANDARD TABLE OF tline.

e_header-tdobject = 'ZCHD_OBJ'.

e_header-tdid = 'Y0B1'.

e_header-tdspras = sy-langu.

e_header-tdlinesize = 72.

CONCATENATE p_Devobjid e_header-tdid INTO e_header-tdname.

CALL FUNCTION 'READ_TEXT'

EXPORTING client = sy-mandt

id = e_header-tdid

language = e_header-tdspras

name = e_header-tdname

object = 'ZCHD_OBJ'

TABLES lines = i_tline

EXCEPTIONS

id = 1

language = 2

name = 3

not_found = 4

object = 5

reference_check = 6

wrong_access_to_archive = 7

OTHERS = 8.

ENDFORM.

FORM save_comments

DATA: e_header TYPE thead,

i_header TYPE STANDARD TABLE OF thead,

w_tline TYPE tline,

i_tline TYPE STANDARD TABLE OF tline WITH HEADER LINE.

e_header-tdobject = 'ZCHD_OBJ'.

e_header-tdid = 'Y0B1'.

e_header-tdspras = sy-langu.

e_header-tdlinesize = 72.

CONCATENATE y0bs_Dev-objid e_header-tdid INTO e_header-tdname.

APPEND 'DevComments for Obj 1" to i_tline-tdline.

CALL FUNCTION 'SAVE_TEXT'

EXPORTING

client = sy-mandt

header = e_header

savemode_direct = 'X'

TABLES

lines = i_tline

EXCEPTIONS

id = 1

language = 2

name = 3

object = 4

OTHERS = 5.

IF sy-subrc <> 0.

ENDIF.

ENDFORM.