User assigned roles using discord.py - discord.py

Question

I am trying to program a bot using discord.py for a discord server. I want to make a command that would allow users to assign themselves name colors (i.e Red or Blue) I tried to achieve this by creating roles. But I am having some trouble assigning roles using the newest form of discord.py.
#client.command()
async def role(ctx, * role: discord.Role):
user = ctx.message.author
await user.add_roles(role)
Does anyone know how to fix the error I'm getting. The error is given below:
discord.ext.commands.errors.CommandInvokeError: Command raised an exception: AttributeError: 'tuple' object has no attribute 'id'

Answer 1

It seems to me that the issue is the '*'...
If you use your code and add a print line to see what is actually passed to your method you will see this result:
Code
#client.command()
async def role(ctx, * role: discord.Role):
print(role)
user = ctx.message.author
await user.add_roles(role)
Output
(<Role id=671750373761089546 name='Red'>,)
Ignoring exception in command role:
Traceback (most recent call last):
File "/home/dual/PyProjects/Discord/Chandler/env/lib/python3.7/site-packages/discord/ext/commands/core.py", line 79, in wrapped
ret = await coro(*args, **kwargs)
File "main.py", line 57, in role
await user.add_roles(role)
File "/home/dual/PyProjects/Discord/Chandler/env/lib/python3.7/site-packages/discord/member.py", line 616, in add_roles
await req(guild_id, user_id, role.id, reason=reason)
AttributeError: 'tuple' object has no attribute 'id'
The above exception was the direct cause of the following exception:
Traceback (most recent call last):
File "/home/dual/PyProjects/Discord/Chandler/env/lib/python3.7/site-packages/discord/ext/commands/bot.py", line 863, in invoke
await ctx.command.invoke(ctx)
File "/home/dual/PyProjects/Discord/Chandler/env/lib/python3.7/site-packages/discord/ext/commands/core.py", line 728, in invoke
await injected(*ctx.args, **ctx.kwargs)
File "/home/dual/PyProjects/Discord/Chandler/env/lib/python3.7/site-packages/discord/ext/commands/core.py", line 88, in wrapped
raise CommandInvokeError(exc) from exc
discord.ext.commands.errors.CommandInvokeError: Command raised an exception: AttributeError: 'tuple' object has no attribute 'id'
If you remove the '*' and keep everything else the same this is what it looks like:
Code
#client.command()
async def role(ctx, role: discord.Role):
print(role)
user = ctx.message.author
await user.add_roles(role)
Output
Red
Without the '*' the role is added to the user who called the command. This only works if the role is spelled correctly and is case sensitive so I would advise implementing some sort of input validation.
Edit:
This article explains about *args and **kwargs in python. It may be useful to check it out to get a better understanding of how to pass arguments to a function :D