def __init__ ( self, added = None, changed = None, removed = None ):
        # Construct new empty dicts every time instead of using a default value
        # in the method argument, just in case someone gets the bright idea of
        # modifying the dict they get in-place.
        if added is None:
            added = {}
        self.added = added

        if changed is None:
            changed = {}
        self.changed = changed

        if removed is None:
            removed = {}
        self.removed = removed

#-------------------------------------------------------------------------------
#  'TraitDict' class:
#-------------------------------------------------------------------------------
Parameters
dataset/ETHPy150Open enthought/traits/traits/trait_handlers.py/TraitDictEvent.__init__