code: def validate_scopes(value_list):
      
      for value in value_list:
          if value not in current_oauth2server.scopes:
              raise ScopeDoesNotExists(value)
      return True
docs: Validate if each element in a list is a registered scope.
  
      :param value_list: The list of scopes.
      :raises invenio_oauth2server.errors.ScopeDoesNotExists: The exception is
          raised if a scope is not registered.
      :returns: ``True`` if it's successfully validated.