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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 create(self):
 """ Calls various methods sequentially in order to fully build the database. """

        # Calls each of these methods in order.  _populate_from_lines and
        # _update_relations must be implemented in subclasses.
        self._init_tables()
        self._populate_from_lines(self.iterator)
        self._update_relations()
        self._finalize()