def get_previous_sha(self, env, current_sha=None):
        from freight.models import Task, Deploy, TaskStatus

        if current_sha is None:
            current_sha = self.get_current_sha(env)

        if current_sha is None:
            return None

        return db.session.query(
            Task.sha,
        ).filter(
            Deploy.task_id == Task.id,
            Task.app_id == self.id,
            Deploy.environment == env,
            Task.status == TaskStatus.finished,
            Task.sha > current_sha,
        ).order_by(
            Deploy.number.desc(),
        ).limit(1).scalar()
dataset/ETHPy150Open getsentry/freight/freight/models/app.py/App.get_previous_sha/operator `!=` -> `>`