SQL> CREATE FUNCTION mhe_restrict
  2  Return NUMBER
  3  Is
  4    PRAGMA RESTRICT_REFERENCES(mhe_restrict, 'WNDS');
  5  Begin
  6    Return 0;
  7  End;
  8  /

Warning: Function created with compilation errors.

SQL> sho err
Errors for FUNCTION MHE_RESTRICT:

LINE/COL ERROR
-------- -----------------------------------------------------------------
4/10     PLS-00708: Pragma RESTRICT_REFERENCES must be declared in a
         package specification