Making a Discord Bot in Python 3

bot.py

# bot.py
import discord


# command handler class

class CommandHandler:

    # constructor
    def __init__(self, client):
        self.client = client
        self.commands = []

    def add_command(self, command):
        self.commands.append(command)

    def command_handler(self, message):
        for command in self.commands:
            if message.content.startswith(command['trigger']):
                args = message.content.split(' ')
                if args[0] == command['trigger']:
                    args.pop(0)
                    if command['args_num'] == 0:
                        return self.client.send_message(message.channel,str(command['function'](message, self.client, args)))
                        break
                    else:
                        if len(args) >= command['args_num']:
                            return self.client.send_message(message.channel,str(command['function'](message, self.client, args)))
                            break
                        else:
                            return self.client.send_message(message.channel, 'command "{}" requires {} argument(s) "{}"'.format(command['trigger'], command['args_num'], ', '.join(command['args_name'])))
                            break
                else:
                    break


# create discord client
client = discord.Client()
token = 'NDI3MjIyOTExMjg0NDEyNDQ2.DZhfMA.h3sx9iq6vO_ROYtlxHHTSZJz0xs'

# create the CommandHandler object and pass it the client
ch = CommandHandler(client)


# command's functions

## start hello command
def hello_function(message, client, args):
    try:
        return 'Hello {}, Argument One: {}'.format(message.author, args[0])
    except Exception as e:
        return e
ch.add_command({
    'trigger': '!hello',
    'function': hello_function,
    'args_num': 1,
    'args_name': ['string'],
    'description': 'Will respond hello to the caller'
})
## end hello command


# bot is ready
@client.event
async def on_ready():
    try:
        print(client.user.name)
        print(client.user.id)

    except Exception as e:
        print(e)


# on new message
@client.event
async def on_message(message):
    
    # if the message is from the bot itself ignore it
    if message.author == client.user:
        pass
    else:
        
        # try to evaluate with the command handler
        try:
            await ch.command_handler(message)
            
        # message doesn't contain a command trigger
        except TypeError as e:
            pass
        
        # generic python error
        except Exception as e:
            print(e)


# start bot
client.run(token)