uri = QgsDataSourceUri()
        # set host name, port, database name, username and password
        uri.setConnection("geoerpdev2", "5432", "LAIS_SPACIAL", "postgres", "Passsword")
        # set database schema, table name, geometry column and optionally
        # subset (WHERE clause)

        uri.setDataSource("spacial", "parcels", "geom","cell_code=3030404")
        if uri:
            print (uri)

        vlayer = QgsVectorLayer(uri.uri(), "parcels", "postgres")
        if not vlayer.isValid():
            print (uri)
            print (vlayer)
        QgsProject.instance().addMapLayers([vlayer])

<qgis._core.QgsDataSourceUri object at 0x000002F5CA5C9EE8>
<qgis._core.QgsVectorLayer object at 0x000002F5CA5E8C18>
dbname='LAIS_SPACIAL' host=geoerpdev2 port=5432 user='postgres' password='Password' table="spacial"."parcels" (geom) sql=cell_code=3030404