FWIW,

use strict;
use warnings;

my %hash = (
            accesslevels => {
                             function => {
                                          func1 =>   {
                                                      content => 'val1
+'
                                                     },
                                          default => {
                                                      content => 'val2
+'
                                                     }
                                         }
                            }
           );

sub flatten {
  my $hash = shift;
  while ( my ( $k, $v ) = each %$hash ) {
    next unless ref $v eq 'HASH';
    flatten( $v );
    exists $v->{ $_ } and $hash->{ $k } = $v->{ $_ }
      for qw( function content )
  }
}

use Dumpvalue;

flatten( \%hash );
print Dumpvalue->new->dumpValue( \%hash );

__END__
'accesslevels' => HASH(0x814cad4)
   'default' => 'val2'
   'func1' => 'val1'
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