@type t() :: %ExOanda.Position{
  commission: float() | nil,
  dividend_adjustment: float() | nil,
  financing: float() | nil,
  guaranteed_execution_fees: float() | nil,
  instrument: ExOanda.Type.Atom.t() | nil,
  long: ExOanda.PositionSide.t() | nil,
  margin_used: float() | nil,
  pl: float() | nil,
  resettable_pl: float() | nil,
  short: ExOanda.PositionSide.t() | nil,
  unrealized_pl: float() | nil
}