I was trying to follow your code. but not working. Can you see if anything is missing:

#!/usr/bin/python
from beem import Steem
from beem.comment import Comment


stm = Steem(node="https://api.steem.house",keys=["MY_POSTING_KEY"])
author = "unnikuttan"
authorperm = "@dexterdev/iran-bites-me-again-it-seems-contest-1-steem-gift-inside"
with open('reply_body.md') as f:
    body = f.read()
c = Comment(authorperm, steem_instance=stm)
c.reply(body, author=author)

I have also prepared this file: reply_body.md

I am getting error like this:

@holger80 Can you help me? Thank you.