Answers for "how to assign a role to a reaction discord.py"

add role discord .py

member = message.author
var = discord.utils.get(message.guild.roles, name = "role name")
member.add_role(var)

reaction role discord.py

@bot.command(pass_context=True)
async def giverole(ctx, user: discord.Member, role: discord.Role):
    await user.add_roles(role)
    await ctx.send(f"hey {ctx.author.name}, {user.name} has been giving a role called: {role.name}")