@type t() :: %DocuSign.Model.SigningGroups{
  created: String.t() | nil,
  createdBy: String.t() | nil,
  errorDetails: DocuSign.Model.ErrorDetails.t() | nil,
  groupEmail: String.t() | nil,
  groupName: String.t() | nil,
  groupType: String.t() | nil,
  modified: String.t() | nil,
  modifiedBy: String.t() | nil,
  signingGroupId: String.t() | nil,
  users: [DocuSign.Model.SigningGroupUser.t()] | nil
}