sub method {
        my $self = $_[0]; # leave it alone for obj/hashref
        unless( ref( $self ) || !$#_ ) { # else is immed. hash or
                                 # list of pairs
                my %opt = @_;
                $self = \%opt;
        }

        # now $self can be processed as a hashref whichever
        # of the four calling styles was used
}