Highscore sys

while True:
    hiscore = int(input('Enter score: '))
    scoreDocument = 'score.txt'

    def saveHiScore(docName):
        if hiscore > getSavedScore(docName):
            docW = open(docName,'w')
            docW.write(str(hiscore))
            docW.close()

    def checkScoreDoc(docName):
        doc = open(docName,'r')
        document = []
        for line in doc:
            score = line.strip()
            document.append(score)
        doc.close()
        if len(document) != 1:
            docW = open(docName,'w')
            docW.write(str(hiscore))
            docW.close()
        elif len(document) == 1:
            return
        else:
            docW = open(docName,'w')
            docW.write('0')
            docW.close()

    def getSavedScore(docName):
        checkScoreDoc(docName)
        doc = open(docName,'r')
        for line in doc:
            saved_score = line.strip()
        doc.close()

        return int(saved_score)

    saveHiScore(scoreDocument)

    print('Highscore: '+str(getSavedScore(scoreDocument)))