title: PL/SQL: testing functions that return Boolean value
body: <p>I am trying to test a PL/SQL function that returns a Boolean value. When I try to do this using the code below I get the error: </p>
  
  <blockquote>
    <p>ORA-06550: Expression is of wrong type. </p>
  </blockquote>
  
  <pre><code>declare   
   v1 boolean; 
  begin 
     select plsql_package.plsql_function('arg1', 'arg2') into v1 from dual;
     dbms_output.put_line('result = ' || v1);
  end; 
  </code></pre>