code: def stats(self):
          
          out = []
          try:
              out += [("Triples", len(self.rdfgraph))]
          except:
              pass
          out += [("Classes", len(self.classes))]
          out += [("Properties", len(self.properties))]
          out += [("Annotation Properties", len(self.annotationProperties))]
          out += [("Object Properties", len(self.objectProperties))]
          out += [("Datatype Properties", len(self.datatypeProperties))]
          out += [("Skos Concepts", len(self.skosConcepts))]
          # out += [("Individuals", len(self.instances))]
          return out
docs: shotcut to pull out useful info for a graph 
  
          2016-08-18 the try/except is a dirty solution to a problem
          emerging with counting graph lenght on cached Graph objects..
          TODO: investigate what's going on..