sub joe_method {
    my $self = ref ($_[0] eq 'SCALAR') ? getSessionHashRef(shift) : shift;

    # getSessionHashRef exists in base class, or...
    # MyApacheSessionHelper->getSessionHashRef (shift)
    ...
}
##</code><code>##

sub joe_method {
    my $self = ref (shift eq 'SOAP::Lite') ? getSessionHashRef(shift) : $_;
...
}