my $hash = {
  File => {
    value => "foo",
    Header => { 
      Key => { 
        value => "phy",
      },
      Version => {
        value => 1.0,
      },
      Revision => {
        log => {
          value => 0
        },
        phy => {
          value => 0
        },
        oth => {
          value => 0
        }
      },
      Contents => {
        Flags => {},
        Dictionary => {},
        Properties => {}
      },
      Precision => {
        Units => {
          value => "mil"
        },
        Dec => {
          value => 1
        }
      }
    }
  }
};