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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 drop_table(self, model_class):
        '''
        Drops the database table of the given model class, if it exists.
        '''
        if model_class.is_system_model():
            raise DatabaseException("You can't drop system table")
        self._send(model_class.drop_table_sql(self))