@classmethod
def fromSubshellsAndOccupancies(cls, subshells, occupancies):
    value = ','.join((f'{subshell:s}{occupancy:d}' for (subshell, occupancy) in zip(subshells, occupancies)))
    return cls(value=value)
@classmethod
def fromSubshellsAndOccupancies(cls, subshells, occupancies):
    value = ','.join((f'{subshell:s}{occupancy:d}' for (subshell, occupancy) in zip(subshells, occupancies)))
    return cls(value=value)