def activate():
    '''Activate an existing user (validate their email confirmation)'''
    email = click.prompt('Email')
    user = User.objects(email=email).first()
    if not user:
        exit_with_error('Invalid user')
    if user.confirmed_at is not None:
        exit_with_error('User email address already confirmed')
        return
    user.confirmed_at = datetime.utcnow()
    user.save()
    success('User activated successfully')
Activate an existing user (validate their email confirmation)