sub can {
	my ($self, $meth) = @_;
	my $class = ref $self || $self;
	my $subref = *{$class . '::' . $meth}{CODE};
	return $subref if defined $subref;
	for (@{$class . '::ISA'}) {
		$subref = $_->can($meth);
		return $subref if defined $subref;
	}
	return undef;
}