SQL> create or replace package emp_pkg as
  2  function f_fun1 return number;
  3  end emp_pkg;
  4  /

Package created.

SQL> create or replace package body emp_pkg as
  2  a number;
  3  function f_fun1 retrun number is
  4  begin
  5  return 10;
  6  end f_fun1;
  7  begin
  8  dbms_output.put_line('Executing one-time-only');
  9  end emp_pkg;
 10  /

Warning: Package Body created with compilation errors.

SQL> show errors
Errors for PACKAGE BODY EMP_PKG:

LINE/COL ERROR
-------- -----------------------------------------------------------------
3/19     PLS-00103: Encountered the symbol "RETRUN" when expecting one of
         the following:
         ( return
         The symbol "return was inserted before "RETRUN" to continue.