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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 migrate(self, conn):
 """Migrate a database as needed. This method is safe to call on an up-to-date database, on an old database, on a newer database, or an uninitialized database (version 0). This method is idempotent. """

        while self.should_migrate(conn):
            current_version = get_user_version(conn)
            migration = self._get_migration(current_version)
            assert migration.from_ver == current_version
            logger.info(f'Migrating database from {migration.from_ver}'
                        f' to {migration.to_ver}')
            self._migrate_single(conn, migration)
            set_user_version(conn, migration.to_ver)
            logger.info(f'Migrated database to {migration.to_ver}')