sub validate_object
{
  my ($self, @interfaces) = @_;
  error unless ref($self);
  foreach my $interface (@interfaces)
  {
    my $fn = $interface . "::is_implemnted_by";
    error unless $fn->($self);
  }
}

#...

sub foo
{
  my ($self) = @_;
  validate_object($self, qw/InterfaceA InterfaceB InterfaceC/);
}

sub bar
{
  my ($self) = @_;
  validate_object($self, map {"Interface$_"} qw/A B D/);
}