puppet key from hiera

I have a puppet manifest that contains this phrase, used to set up mysql configuration files:

# Qualified keys aren't available until hiera 2.0.
$mysql_config = hiera('web_mysql_server')
'production' => {
  adaptor  => 'mysql2',
  database => $mysql_config['mysql_database'],
  user     => $mysql_config['mysql_useame'],
  password => $mysql_config['mysql_password'],
  host     => '0.0.0.0',
  encoding => 'UTF8',
},

But sometimes I'd maybe like the database to be a staging database, and so it's a bit confusing to call it production. No problem, I've recently leaed about hiera, it's my hammer for all nails today:

$mysql_config['mysql_name'] => {
  adaptor  => 'mysql2',
  database => $mysql_config['mysql_database'],
  user     => $mysql_config['mysql_useame'],
  password => $mysql_config['mysql_password'],
  host     => '0.0.0.0',
  encoding => 'UTF8',
},

No, that doesn't work, though the error ("syntax error at line (...with '=>'...), expected '}'") isn't terribly revealing.

("Key" might be the wrong word. Please correct me. I'm a bit new to puppet. And that itself may be why I've not been able to answer this question by googling and reading.)

Thanks for any pointers.