Previously you would use gettext as following:
gettext
_(\'Hey {},\').format(username)
but what about new Python\'s f-string?
'Hey {},' is contained in your translation dictionary as is.
'Hey {},'
If you use f'Hey {username},', that creates another string, which won't be translated.
f'Hey {username},'
In that case, the format method remains the only one useable.
format