@type t() :: %LineDrive.Activity{
  busy_flag: boolean() | nil,
  deal_id: pos_integer() | nil,
  done: (0 | 1) | nil,
  due_date: Date.t() | nil,
  due_time: String.t() | nil,
  duration: String.t() | nil,
  id: pos_integer() | nil,
  lead_id: pos_integer() | nil,
  location: String.t() | nil,
  note: String.t() | nil,
  org_id: pos_integer() | nil,
  org_name: String.t() | nil,
  participants: [LineDrive.ActivityParticipant.t()] | nil,
  person_id: pos_integer() | nil,
  public_description: String.t() | nil,
  subject: String.t(),
  type: LineDrive.ActivityType.key_string(),
  user_id: pos_integer() | nil
}