Oracle Message PLS-00503 - RETURN statement required for this return from function

ERRORRETURN statement required for this return from function
CAUSEIn a function body, a RETURN statement was used that contains no expression. In procedures, a RETURN statement contains no expression because the statement simply returns control to the caller. However, in functions, a RETURN statement must contain an expression because its value is assigned to the function identifier.
ACTIONAdd an expression to the RETURN statement.