def validShareFields(self, share, fields):
        if (len(fields) > 1) and ('value' in fields):
            return False

        if share: #does share have fields already
            for field in fields:
                if field  not in share: #so this field could be added to share
                    if ('value' in share) or (field == 'value'):
                        return False

        return True
Validates that updating fields in share won't violate the
dataset/ETHPy150Open ioflo/ioflo/ioflo/base/building.py/Builder.validShareFields