code: def to_gremlin(self):
          
          # We can't directly pass a Date or a DateTime object, so we have to pass it as a string
          # and then parse it inline. For date format parameter meanings, see:
          # http://docs.oracle.com/javase/7/docs/api/java/text/SimpleDateFormat.html
          if GraphQLDate.is_same_type(self.inferred_type):
              return u'Date.parse("{}", {})'.format(STANDARD_DATE_FORMAT, self.variable_name)
          elif GraphQLDateTime.is_same_type(self.inferred_type):
              return u'Date.parse("{}", {})'.format(STANDARD_DATETIME_FORMAT, self.variable_name)
          else:
              return six.text_type(self.variable_name)
docs: Return a unicode object with the Gremlin representation of this expression.