How to change CL_SALV_TABLE=>FACTORY ALV Field Label

REPORT zmk_adv_sql_01.
Data: o_alv TYPE ref to CL_SALV_TABLE,
      l_Column TYPE REF TO CL_SALV_column.

Select vbeln, posnr, matnr, netpr,smeng , ( netpr * smeng ) as fin_amt
into table @data(itab_vbap_hana)
from zvbap .

cl_salv_table=>factory( importing R_SALV_TABLE = data(ol_alv) changing t_table = itab_vbap_hana ).

data(ol_col) = ol_alv->get_columns( ).

" Setting Column Name

l_column ?= ol_col->get_column( 'FIN_AMT' ).
l_column->set_long_text( 'Final Amount' ).
l_column->set_medium_text( 'Final Amount' ).
l_column->set_short_text( 'Fin Amount' ).


" Display ALV
ol_alv->display( ).