{
  'approval_id': <str>,
  'approver'?: {
    'bot'?: <bool>,
    'display_name': <str>,
    'email': <str>,
    'user_id': <str>,
  },
  'changed'?: <datetime>,
  'note': <str>,
  
  # This is the dictionary provided on this page listed
  # under "Reservation".
  'reservation': <dict>,
  
  # One of: 'approved', 'denied', 'pending'.
  'status': <str>,
}