title: Function create and call
body: <p>I created this function, but once i try to call it, i get an error.</p>
  
  <p>Function : </p>
  
  <pre><code>CREATE OR REPLACE FUNCTION check_email (
      p_user IN users.user_id%TYPE
  ) RETURN BOOLEAN AS
      p_email users.email%TYPE;
  BEGIN
      SELECT
          email
      INTO p_email
      FROM
          users
      WHERE
          user_id = p_user;
  
      IF p_email IS NULL THEN
          RETURN false;
      ELSE
          RETURN true;
      END IF;
  END check_email;
  </code></pre>
  
  <p>Calling the function: </p>
  
  <pre><code>declare
  result boolean := check_email(1);  
  begin
  DBMS_OUTPUT.put_line(result);
  end;
  </code></pre>
  
  <p>Error: 
  <strong>PLS-00306: wrong number or types of arguments in call to 'PUT_LINE'</strong></p>