Get Created Assignment Number through create_secondary_emp_asg

I'm creating a Secondary assignment number by using HR_ASSIGNMENT_API.CREATE_SECONDARY_EMP_ASG API as shown in the sample below (please note the variable ln_assignment_number):

set serveroutput on;declare    cursor ict_emp_dtls_cur is    select        -- New Details            lin.ICT_TRX_LINE_ID         ICT_TRX_LINE_ID        ,   lin.CURRENT_ASSIGNMENT_ID   CURRENT_ASSIGNMENT_ID        ,   LIN.EMPLOYEE_NUMBER         EMPLOYEE_NUMBER        ,   LIN.NEW_PAYROLL_ID          NEW_PAYROLL_ID        ,   LIN.NEW_JOB_ID              NEW_JOB_ID        ,   LIN.NEW_ORG_ID              NEW_ORG_ID        ,   LIN.NEW_LOCATION_ID         NEW_LOCATION_ID        ,   LIN.NEW_PAY_BASIS_ID        NEW_PAY_BASIS_ID        ,   LIN.NEW_SUPERVISOR_ID       NEW_SUPERVISOR_ID        ,   LIN.NEW_PROJECT_NUMBER      NEW_PROJECT_NUMBER        ,   LIN.NEW_KRONOS_TERMINAL     NEW_KRONOS_TERMINAL        ,   LIN.NEW_EMP_CAT_CODE        NEW_EMP_CAT_CODE        ,   LIN.NEW_SALARY              NEW_SALARY        ,   LIN.NEW_ADDRESS_LINE_1      NEW_ADDRESS_LINE_1        ,   LIN.NEW_ADDRESS_LINE_2      NEW_ADDRESS_LINE_2        ,   LIN.NEW_ADDRESS_LINE_3      NEW_ADDRESS_LINE_3        ,   LIN.NEW_CITY                NEW_CITY        ,   LIN.NEW_STATE               NEW_STATE        ,   LIN.NEW_ZIP                 NEW_ZIP        ,   LIN.NEW_COUNTY              NEW_COUNTY        -- Current Asg Details        ,   PPX.*        -- SCL        ,   scl.segment1                scl_segment1        ,   scl.segment2                scl_segment2        ,   scl.segment3                scl_segment3        ,   scl.segment4                scl_segment4        ,   scl.segment5                scl_segment5        ,   scl.segment6                scl_segment6        ,   scl.segment7                scl_segment7        ,   scl.segment8