$self->option('field');
        returns value of field

  $self->option(%hash);
        sets values of fields in hash:  field=>value,field=>value. . .  
        returns:  reference to a hash of old values;
                  if the field is not a valid option
                  the field's value is set to undef;
                    
                  Because an old value may have been undefined and returns undef
                  you must use either validOption() or invalidOption()
                  to determine whether the field is in fact invalid 
                    

    $opt->validOption(<option>)
    $opt->invalidOption(<option>)

These test for validity of options which have been set with the option setting functions, either option() or the set_<option>() family. An invalid result occurs when attempting to set an option which does not exist.