code: def get_unique_constraints(self, connection, table_name,
                                 schema=None, **kw):
          
          constraints = self._get_redshift_constraints(connection,
                                                       table_name, schema, **kw)
          constraints = [c for c in constraints if c.contype == 'u']
          uniques = defaultdict(lambda: defaultdict(dict))
          for con in constraints:
              uniques[con.conname]["key"] = con.conkey
              uniques[con.conname]["cols"][con.attnum] = con.attname
  
          return [
              {'name': None,
               'column_names': [uc["cols"][i] for i in uc["key"]]}
              for name, uc in uniques.items()
          ]
docs: Return information about unique constraints in `table_name`.
  
          Overrides interface
          :meth:`~sqlalchemy.engine.interfaces.Dialect.get_unique_constraints`.