':param id: Container Image id.
:type id: ``str``
:param name: The name of the image.
:type  name: ``str``
:param driver: ContainerDriver instance.
:type driver: :class:`.ContainerDriver`
:param extra: (optional) Extra attributes (driver specific).
:type extra: ``dict``'

def __init__(self, id, name, driver, extra=None):

    self.id = (str(id) if id else None)
    self.name = name
    self.driver = driver
    self.extra = (extra or {})
