code: 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'f 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')
docs: Activate an existing user (validate their email confirmation)