{
  "f1": [
    "string",
    /* ... */
  ],
  "f2": [
    "f2-1",
    /* ... */
  ],
  "f3": [
    "f3-1",
    "f3-2",
    /* ... */
  ],
  // Optional
  "f4": [
    "f4-1",
    "f4-2",
    "f4-3",
    /* ... */
  ],
  // Must contain exactly 2 elements
  "f5": [
    "f5-1",
    /* ... */
  ],
  // Must contain exactly 2 elements
  "f6": [
    "f6-1",
    "f6-2",
  ]
}