# untested
foreach my $key ( keys %{JSON::PP->new->decode($json_data)}  ){

 # some collision check?
 if ( exists $$href{ $key }){
    warn "$key already exists! was [$$href{ $key }] and will be [${JSON::PP->new->decode($json_data)}{$key}]\n";
 }

 # assign a new key value pair
 
 $$href{$key} = ${JSON::PP->new->decode($json_data)}{$key};


}