def save(self, doc):
        if doc.id:
            return self.update(doc)
        else:
            return self.insert(doc)
def _visit_migrate_unique_constraint(self, *p, **k):
    """Drop the given unique constraint

    The corresponding original method of sqlalchemy-migrate just
    raises NotImplemented error

    """

    self.recreate_table(p[0].table, omit_uniques=[p[0].name])