code: def _UpdateUserGroups(self, user, groups):
      
      groups = ','.join(groups)
      self.logger.debug('Updating user %s with groups %s.', user, groups)
      command = self.usermod_cmd.format(user=user, groups=groups)
      try:
        subprocess.check_call(command.split(' '))
      except subprocess.CalledProcessError as e:
        self.logger.warning('Could not update user %s. %s.', user, str(e))
        return False
      else:
        self.logger.debug('Updated user account %s.', user)
        return True
docs: Update group membership for a Linux user.
  
      Args:
        user: string, the name of the Linux user account.
        groups: list, the group names to add the user as a member.
  
      Returns:
        bool, True if user update succeeded.