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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 get_placeholder_data(self, request, obj):
 """ Get placeholder data from layout. """

        if not obj or not getattr(obj, 'layout', None):
            data = [PlaceholderData(slot='main', role='m', title='Main')]
        else:
            data = obj.layout.get_placeholder_data()
        return data