import csv

class CSVEntry:
    def __init__(self, **kvargs):
        assert ( set(kvargs.keys()) - set(self.__class__.fields) ) == set()
        for field in self.__class__.fields:
            setattr(self, field, kvargs[field] or "")

    @classmethod
    def fromRow(cls, row):
        assert len(row) == len(cls.fields)
        return cls(**{ field : value for field,value in zip(cls.fields, row)})

    def toRow(self):
        return list(getattr(self,field) for field in self.__class__.fields)

    @classmethod
    def loadFile(cls, file):
        with open(file) as csvfile:
            reader = csv.reader(csvfile)
            return list( cls.fromRow(row) for row in reader )

    @staticmethod
    def saveFile(file, entries):
        with open(file,"w") as csvfile:
            writer = csv.writer(csvfile)
            writer.writerows( entry.toRow() for entry in entries )