TypeError: object function can't be used in await expression

I have created an async function called add_reaction_tasks which maps specific function to dictionary keys. This function returns the dictionary to a variable called tasks which is located in the event on_raw_reaction_add.

The first issue is that tasks = await add_reaction_tasks() raises the following error: line 343, in _run_event await coro(*args, **kwargs).

The second one is when I try to access the dictionary, denoted by tasks, with the key which_trigger and the argument payload, the following error is raised:

'1' : await add_rules_messages_tasks, TypeError: object function can't be used in 'await' expression.

I have made sure that await is used where possible. Besides that, I am not sure what else I have to get done, to make this code work.

The code snippets:

1) the functions used in add_reaction_tasks

def display_messages_error(payload = discord.RawReactionActionEvent):
                            ...
async def add_rules_messages_tasks(payload = discord.RawReactionActionEvent):
                            ...
async def add_years_messages_tasks(payload = discord.RawReactionActionEvent):
                            ...
async def add_programming_languages(payload = discord.RawReactionActionEvent):
                            ...

2) add_reaction_tasks function

async def add_reaction_tasks():
    add_tasks = {
                    '0' : display_messages_error,
                    '1' : await add_rules_messages_tasks,
                    '2' : await add_years_messages_tasks,
                    '3' : await add_programming_languages
                }
    
    return add_tasks

3) on_raw_reaction_add event

@bot.event
@commands.bot_has_permissions(manage_roles = True)
async def on_raw_reaction_add(payload : discord.RawReactionActionEvent):
    role  = None
    guild = None
    # if the guild is server_name
    if payload.guild_id == server_id:
        guild = find(lambda g : g.id == server_id, bot.guilds)
    
    member = get(guild.members, id = payload.user_id)

    if not guild: return
    if not member: return

    which_trigger = 0 # 0 stands for invalid message id (should trigger display_message_error function)
    try:
        which_trigger = str(all_role_reaction_ids[str(payload.message_id)]) # <= looks weird, but works
        #print(f'\nwhich_trigger = {which_trigger}\n')
    except KeyError as err:
        print(f'KeyError: {err}')
        print('Invalid role-reaction message id')
        return

    tasks = await add_reaction_tasks()  # <= first error
    
    await tasks[which_trigger](payload) # <= second error

    return