Admin Permissions - LonamiWebs/Telethon GitHub Wiki

Giving or revoking admin permissions can be done with the following code:

# Give admin permissions to user in chat/channel
client.edit_admin(channel, who, is_admin=True)

# Revoke admin for user in chat/channel
client.edit_admin(channel, who, is_admin=False)

Note that you can also deny/allow specific permissions for an admin using the positional arguments of edit_admin. More about this method and the arguments it takes here.

Thanks to @Kyle2142 for pointing out that you cannot set to True the post_messages and edit_messages fields. Those that are None can be omitted (left here so you know which are available).