# assuming $obj->{attr_name} holds a hashref
  return $obj->{attr_name};
}

# code passes

foreach my $item (keys %{ $obj->method() }) {

##</code><code>##

my %hash    = qw(foo bar baz quux);
my $hashref = \%hash;
my @list    = qw(ichi ni san shi);
my $lisref  = \@list;
 
keys %hash;          # valid
keys %$hashref;      # valid
keys %{{@list}};     # valid
keys %{{@$listref}}; # valid
keys $hashref;       # invalid
keys %{@list};       # invalid