cannot add channel to group named channel_name

[aryaniyaps]

In my consumer, on connect, I add the user to their own private channel.
As the user is anonymous when connecting, I use the channel_name as an identifier and create a private channel with it.

    async def connect(self):
        # add the user to their private group. Because
        # we add the user before they identify themselves
        # via the gateway we cannot get the user's id.
        # Hence we use the channel name as a substitute
        # for the private group's unique identifier.
        await self.channel_layer.group_add(
            group=self.channel_name,
            channel=self.channel_name
        )
        await self.accept()
        # indicate the user that they have
        # connected to the gateway successfully.
        await self.hello()

something like this.
However, I am getting ASCII string errors.
traceback:

File "C:\Users\iyapp\PycharmProjects\rebox\plixn_django\apps\gateway\consumers.py", line 79, in connect
    await self.channel_layer.group_add(
  File "C:\Users\iyapp\Envs\rebox_django\lib\site-packages\channels_redis\core.py", line 618, in group_add
    assert self.valid_group_name(group), "Group name not valid"
  File "C:\Users\iyapp\Envs\rebox_django\lib\site-packages\channels\layers.py", line 165, in valid_group_name
    raise TypeError(
TypeError: Group name must be a valid unicode string containing only ASCII alphanumerics, hyphens, or periods.

If I cannot use the channel_name as a unique identifier, are there any alternatives?
If I am not wrong, this was the recommended way of adding users to their own channels earlier.

[carltongibson]

What is the channel name?

[aryaniyaps]

print(self.channel_name)
>>> specific.d8badfcd25af40728ba1d2d1cea4efbf!ad4a18d60be74b3dad7f916a69c82aad

@carltongibson here it is

[carltongibson]

So this'll will be the issue: !.

...are there any alternatives?

Remove the !, split and use part of the name, ... — lots of options, you just need to decide on one I think