Run "up" a migration instance.

        :type migration_file: str

        :type batch: int

        :type pretend: bool

def _run_up(self, path, migration_file, batch, pretend=False):
        """
        Run "up" a migration instance.

        :type migration_file: str

        :type batch: int

        :type pretend: bool
        """
        migration = self._resolve(path, migration_file)

        if pretend:
            return self._pretend_to_run(migration, "up")

        if migration.transactional:
            with migration.db.transaction():
                migration.up()
        else:
            migration.up()

        self._repository.log(migration_file, batch)

        self._note(
            decode("[<info>OK</>] <info>Migrated</info> ")
            + "<fg=cyan>%s</>" % migration_file
        )