<Tr> <Td> Lily Tomlin </Td> <Td> Frances' Frankie' Bergstein </Td> <Td_colspan="5"> Lead </Td> </Tr> <Tr> <Td> Sam Waterston </Td> <Td> Sol Bergstein--Hanson </Td> <Td_colspan="5"> Lead </Td> </Tr> <Tr> <Td> Martin Sheen </Td> <Td> Robert Bergstein--Hanson </Td> <Td_colspan="5"> Lead </Td> </Tr> <Tr> <Td> Brooklyn Decker </Td> <Td> Mallory Hanson </Td> <Td_colspan="5"> Main </Td> </Tr>

Who plays frankies sister in season 4 of grace and frankie