ORACLE PL/SQL

I WANT TO MODIFY THE PACKAGE:
1-FUNCTION SHIP_NAME_PF SHOULD BE USED ONLY FROM WITHIN THIS PACKAGE.
2-ADD TO BASKET_INFO-PP PROCEDURE SO THAT THAT IT RETURN NAME SHIPPED TO BY USING FUNCTION SHIP_NAME_PF
3-CREATE AN ANONYMOUSE BLOCKS THAT WILL INVOKE THE PROCEDURE WITH THE NEW MODIFICATIONS.
 THE ORIGINAL PACKAGE IS :
CREATE OR REPLACE PACKAGE order_info_pkg IS
 FUNCTION ship_name_pf  
   (p_basket IN NUMBER)
   RETURN VARCHAR2;
 PROCEDURE basket_info_pp
  (p_basket IN NUMBER,
   p_shop OUT NUMBER,
   p_date OUT DATE);
END;
/
CREATE OR REPLACE PACKAGE BODY order_info_pkg IS
 FUNCTION ship_name_pf  
   (p_basket IN NUMBER)
   RETURN VARCHAR2
  IS
   lv_name_txt VARCHAR2(25);
 BEGIN
  SELECT shipfirstname||' '||shiplastname
   INTO lv_name_txt
   FROM bb_basket
   WHERE idBasket = p_basket;
  RETURN lv_name_txt;
 EXCEPTION
   WHEN NO_DATA_FOUND THEN
     DBMS_OUTPUT.PUT_LINE('Invalid basket id');
 END ship_name_pf;
 PROCEDURE basket_info_pp
  (p_basket IN NUMBER,
   p_shop OUT NUMBER,
   p_date OUT DATE)
  IS
 BEGIN
   SELECT idshopper, dtordered
    INTO p_shop, p_date
    FROM bb_basket
    WHERE idbasket = p_basket;
 EXCEPTION
   WHEN NO_DATA_FOUND THEN
     DBMS_OUTPUT.PUT_LINE('Invalid basket id');
 END basket_info_pp;
END;
/

i DELETED THE FUNCTION DECLARATION FROM THE PACKAGE SPEC. AND THEN i USED THE FUNCTION IN THE SELECT STATEMENT OF THE PROCEDURE BUT i GET PL/00231 ERROR. THE MODIFIED PACKAGE CODE IS

CREATE OR REPLACE PACKAGE order_info_pkg IS
 
 PROCEDURE basket_info_pp
  (p_basket IN NUMBER,
   p_shop OUT NUMBER,
   p_date OUT DATE,
   p_name OUT VARCHAR2);
END;
/
CREATE OR REPLACE PACKAGE BODY order_info_pkg IS
 FUNCTION ship_name_pf  
   (p_basket IN NUMBER)
   RETURN VARCHAR2
  IS
   lv_name_txt VARCHAR2(25);
 BEGIN
  SELECT shipfirstname||' '||shiplastname
   INTO lv_name_txt
   FROM bb_basket
   WHERE idBasket = p_basket;
  RETURN lv_name_txt;
 EXCEPTION
   WHEN NO_DATA_FOUND THEN
     DBMS_OUTPUT.PUT_LINE('Invalid basket id');
 END ship_name_pf;
 PROCEDURE basket_info_pp
  (p_basket IN NUMBER,
   p_shop OUT NUMBER,
   p_date OUT DATE,
   p_name OUT VARCHAR2)
  IS
 BEGIN
   SELECT idshopper, dtordered, ship_name_pf(p_basket)
    INTO p_shop, p_date,p_name
    FROM bb_basket
    WHERE idbasket = p_basket;
 EXCEPTION
   WHEN NO_DATA_FOUND THEN
     DBMS_OUTPUT.PUT_LINE('Invalid basket id');
 END basket_info_pp;
END;
/

would you tell me how to fix the problem?