Simple sample to read a file and return the output

school.py

from errbot import BotPlugin, botcmd
from os.path import join

DAYS_PATH = 'f:/errplugins/'

class School(BotPlugin):
    @botcmd 
    def missed_day(self, msg, args):
        """Get missed day and provide assignment summary."""
        with open(join(DAYS_PATH, "summary.%s" % args), 'r') as f:
            return f.read()