DATA pernr TYPE pernr_d VALUE 1.
DATA(time_accounts) = cl_hcmfab_att_abs_bl_apis=>get_instance( )->read_time_accounts( iv_pernr = pernr
iv_begda = sy-datum
iv_endda = sy-datum ). "iv_endda is never used!
cl_demo_output=>display( time_accounts ).
Although there is an obligatory iv_endda parameter, it is never used inside of method read_time_accounts. Instead, there is some logic which checks for a T77S0 Parameter, and it will use either highdate or begda as endda value.
IMO, it would have made sense to mark iv_endda as optional, so it would be downward compatible and the parameter could be omitted on newer releases. Now it is a bit misleading.