Custom command checks in

Often you may find the need to use checks that don't exist by default in Fortunately, provides discord.ext.commands.check which allows you to create you own checks like this:

from discord.ext.commands import check, Context

def in_any_channel(*channels):
  async def predicate(ctx: Context):
    return in channels
  return check(predicate)
This check is to check whether the invoked command is in a given set of channels. The inner function, named predicate here, is used to perform the actual check on the command, and check logic should go in this function. It must be an async function, and always provides a single commands.Context argument which you can use to create check logic. This check function should return a boolean value indicating whether the check passed (return True) or failed (return False).

The check can now be used like any other commands check as a decorator of a command, such as this:

async def ping(ctx: Context):
This would lock the ping command to only be used in the channel 728343273562701984. If this check function fails it will raise a CheckFailure exception, which can be handled in your error handler.