def __init__(self, identifier=None, container=None):

        tlib.Node.__init__(self, identifier=identifier)

        self._childs = []
        self._parent = None
        self._birth_time = None
        self._division_time = None
        self._sdata = {}  # dictionary to contain computed data
        self._protected_against_build = set()  # set of obs not to re-build
        self.container = container  # point to Container instance
        # cells are built from a specific container instance
        # container can be a given field of view, a channel, a microcolony, ...
        return