{
  "account_uid": "<String>",
  "certificate_uid": "<String>",
  "course_uid": "<String>",
  "expire_date": {
    "Enum": [
      {
        "String": [
          "<String>"
        ]
      },
      {
        "Timestamp": [
          "<Timestamp (e.g. `2000-01-01T12:00:00Z`)>"
        ]
      }
    ]
  },
  "hash": "<String of size 64 containing lowercase hex characters.>",
  "issue_date": "<Timestamp (e.g. `2000-01-01T12:00:00Z`)>"
}

{
  "Enum": [
    {
      "ParseParams": []
    },
    {
      "LogFull": []
    },
    {
      "LogMalformed": []
    },
    {
      "OnlyAccount": []
    },
    {
      "AlreadyRegistered": []
    },
    {
      "NotOwner": []
    }
  ]
}

None

"<String of size 64 containing lowercase hex characters.>"

{
  "Enum": [
    {
      "ParseParams": []
    },
    {
      "LogFull": []
    },
    {
      "LogMalformed": []
    },
    {
      "OnlyAccount": []
    },
    {
      "AlreadyRegistered": []
    },
    {
      "NotOwner": []
    }
  ]
}

{
  "Enum": [
    {
      "None": []
    },
    {
      "Some": [
        {
          "account_uid": "<String>",
          "certificate_uid": "<String>",
          "course_uid": "<String>",
          "expire_date": {
            "Enum": [
              {
                "String": [
                  "<String>"
                ]
              },
              {
                "Timestamp": [
                  "<Timestamp (e.g. `2000-01-01T12:00:00Z`)>"
                ]
              }
            ]
          },
          "issue_date": "<Timestamp (e.g. `2000-01-01T12:00:00Z`)>",
          "timestamp": "<Timestamp (e.g. `2000-01-01T12:00:00Z`)>",
          "witness": "<AccountAddress>"
        }
      ]
    }
  ]
}