$inf = {
  test => {
    host1 => {
      app => {
        setting1 => 'foo',
        setting2 => 'bar',
      },
    },
    host2 => {
      app => {
        setting1 => 'baz',
        setting2 => 'buz',
      },
    },
  },
  dev => {
    host3 => {
      app => {
        setting1 => 'a',
        setting2 => 'b',
      },
    },
    host4 => {
      app => {
        setting1 => 'c',
        setting2 => 'd',
      },
    },
  },
};