code: def users_deactivate(user):
      
      user_obj = _datastore.get_user(user)
      if user_obj is None:
          raise click.UsageError('ERROR: User not found.')
      if _datastore.deactivate_user(user_obj):
          click.secho('User "{0}" has been deactivated.'.format(user),
                      fg='green')
      else:
          click.secho('User "{0}" was already deactivated.'.format(user),
                      fg='yellow')
docs: Deactivate a user.