text: import rdflib
  from .graphObject import GraphObject, IdentifierMissingException
  
  
  class Variable(GraphObject):
      def __init__(self, name, **kwargs):
          super(Variable, self).__init__()
          self.var = rdflib.Variable(name)
  
      @property
      def identifier(self):
          raise IdentifierMissingException(self)
  
      def variable(self):
          return self.var
  
      @property
      def defined(self):
          return False
  
      def __hash__(self):
          return hash(self.var)
  
      def __str__(self):
          return str(self.var)
  
      def __repr__(self):
          return "yarom.variable.Variable('"+str(self.var)+"')"
  