human
I wrote the below code

    def prep(r):
        table = r.table
        tablename = 'msg_twitter_channel'
        s3db.configure(tablename, deletable=False)
        if (not r.id):
            query = ((table.deleted == False) & (table.enabled == True))
            record = db(query).select(table.id, limitby=(0, 1))
            if record:
                record_id = record.id
                r.id = record_id
                r.resource.add_filter((table.id == record_id))
                r.method = 'update'
            else:
                r.method = 'create'
        if r.interactive:
            table.twitter_account.label = T('Current    Twitter    account')
            s3.crud_strings[tablename] = Storage(title_display=T('Twitter    Settings'), title_list=T('Twitter    Accounts'), label_create=T('Create    Twitter    Account'), title_update=T('Edit    Twitter    account'), label_list_button=T('View    Twitter    Accounts'), msg_record_created=T('Account    added'), msg_record_deleted=T('Twitter    Account    deleted'), msg_list_empty=T('No    Accounts    currently    defined'), msg_record_modified=T('Twitter    Settings    updated'))
        return True
    s3.prep = prep
    def postp(r, output):
        if r.interactive:
            s3_action_buttons(r)
            table = r.table
            query = (table.deleted == False)
            rows = db(query).select(table.id, table.enabled)
            restrict_e = [str(row.id) for row in rows if (not row.enabled)]
            restrict_d = [str(row.id) for row in rows if row.enabled]
            from s3 import s3_str
            s3.actions += [dict(label=s3_str(T('Enable')), _class='action-btn', url=URL(args=['[id]', 'enable']), restrict=restrict_e), dict(label=s3_str(T('Disable')), _class='action-btn', url=URL(args=['[id]', 'disable']), restrict=restrict_d)]
            if (not s3task._is_alive()):
                s3.actions += [dict(label=s3_str(T('Poll')), _class='action-btn', url=URL(args=['[id]', 'poll']), restrict=restrict_d)]
        return output
    s3.postp = postp
   ...

What's a good function header?

=====
Here's a good function header?
assistant
#Here's a good function header.

def twitter_channel():