Group class missing

[liangduo1993]

Hi team,

In class ESignLiveAPIObjects line 878, attribute group_x in Signer class requires a mapping to Group class, while I can't find where the class is defined.
And once I try to retrieve a package where using a group signer, en error will show up:
Line: 772, Column: 1
ESignLiveRESTAPIHelper.ESignLiveRestAPIHelperException: Error getting the Package: No field name specified on column for sobject of type Group

Currently, as an workaround, I used GroupMembership class instead, but still, it's better to have a specific encapsulation for this model.
And a sample group JSON:
"group_x":{
"name":"test member type_x",
"reciprocalDelegation":false,
"emailMembers":false,
"members":[
{
"pending":true,
"memberType":"REGULAR",
"email":"1@mailinator.com",
"lastName":"Invitee",
"firstName":"Account",
"userId":"KJBZ3qXhsTk6"
},
{
"pending":false,
"memberType":"REGULAR",
"email":"2@mailinator.com",
"lastName":"201",
"firstName":"201",
"userId":"5KT07kJmcZUQ"
}
],
"update_xd":"2018-11-02T14:32:22Z",
"email":"xxx@example.com",
"created":"2018-11-02T14:32:22Z",
"data":null,
"account":null,
"id":"9d00fbec-55ae-4cee-bea3-85ee26fa4123"
}

Best,
Duo Liang