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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def _is_initialized(self, entity):
 """Internal helper to ask if the entity has a value for this Property. This returns False if a value is stored but it is None. """

    return (not self._required or
            ((self._has_value(entity) or self._default is not None) and
             self._get_value(entity) is not None))