sub method {
    my $self= shift(@_);
    croak 'Usage: $oldVal= $obj->method( $idx [, $newVal ] )',$/
      unless  1 <= @_  &&  @_ <= 2;
    my $i= shift(@_);
    my $old= $self->{B}[$i];
    $self->{B}[$i]= shift(@_)   if  @_;
    return $old;
}

##</code><code>##

sub method {
    my $self= shift(@_);
    croak 'Missing $idx; usage: $oldVal= $obj->method( $idx [, $newVal ] )',$/
      unless  @_;
    my $i= shift(@_);
    my $old= $self->{B}[$i];
    $self->{B}[$i]= shift(@_)   if  @_;
    croak 'Too many args; usage: $oldVal= $obj->method( $idx [, $newVal ] )',$/
      if  @_;
    return $old;
}

##</code><code>##

{
    my $usage;
    BEGIN { $usage= '$oldVal= $obj->method( $idx [, $newVal ] )' }

    sub method {
        my $self= shift(@_);
        croak "Missing \$idx; usage: $usage\n"   unless  @_;
        my $i= shift(@_);
        my $old= $self->{B}[$i];
        $self->{B}[$i]= shift(@_)   if  @_;
        croak "Too many args; usage: $usage\n"   if  @_;
        return $old;
    }
}