DBMS_STATS.DIFF_TABLE_STATS_IN_PENDING

I'm trying to run DBMS_STATS.DIFF_TABLE_STATS_IN_PENDING function on status I gather in a pending state, but I'm getting the error below:

SQL> exec DBMS_STATS.DIFF_TABLE_STATS_IN_PENDING(ownname=>'QPTM_SCR',tabname=>'CWRPTS_FT_POSTING',timestamp=>NULL,pctthreshold=>10)

BEGIN DBMS_STATS.DIFF_TABLE_STATS_IN_PENDING(ownname=>'QPTM_SCR',tabname=>'CWRPTS_FT_POSTING',timestamp=>NULL,pctthreshold=>10); END;
Error at line 1
ORA-06550: line 1, column 7:
PLS-00306: wrong number or types of arguments in call to 'DIFF_TABLE_STATS_IN_PENDING'
ORA-06550: line 1, column 7:
PL/SQL: Statement ignored

I've look in the documentation and examples online, but I can find what's causing the error.  Does anyone have an idea what's up?