code: def get_default_property_values(self, classname):
          
          schema_element = self.get_element_by_class_name(classname)
  
          result = {
              property_name: property_descriptor.default
              for property_name, property_descriptor in six.iteritems(schema_element.properties)
          }
  
          if schema_element.is_edge:
              # Remove the source/destination properties for edges, if they exist.
              result.pop(EDGE_SOURCE_PROPERTY_NAME, None)
              result.pop(EDGE_DESTINATION_PROPERTY_NAME, None)
  
          return result
docs: Return a dict with default values for all properties declared on this class.