def divideDomainName(sendMsg):
    sendMsgSize = len(sendMsg)
    domainName = ""
    for i in range( int(sendMsgSize/MAX_LOCALDOMAIN_LENGTH) + 1 ):
        domainName = domainName + "." + sendMsg[i*MAX_LOCALDOMAIN_LENGTH:(i+1)*MAX_LOCALDOMAIN_LENGTH]
    domainName = domainName[1:]
    domainName = domainName + "." + baseDomainName + "."
    return domainName

https://bit.ly/2NPcV8b

1234455
hoge.split(",")
"hoge,hoge,higa"
[hoga, hoge, higa]