code: def validate_permissions(perms):
      
      if not isinstance(perms, (list, tuple)):
          perms = [perms]
      valid_perms = set(PERMISSIONS.values())
      if ALL_PERMISSIONS in perms:
          return perms
      if set(perms) - valid_perms:
          raise ValueError(
              'Invalid ACL permission names. Valid permissions '
              'are: {}'.format(', '.join(valid_perms)))
      return perms
docs: Validate :perms: contains valid permissions.
  
      :param perms: List of permission names or ALL_PERMISSIONS.