code: def to_display(self, fields=None, manytomany=False, dicttype=dict, prefix=''):
          
          d = dicttype()
  
          fields = fields or self.properties.keys()
          for k in fields:
              v = self.properties.get(k)
              if not v: continue
              if prefix:
                  field_name = prefix+k
              else:
                  field_name = k
              if not isinstance(v, ManyToMany):
                  field_value = getattr(self, k)
                  d[k] = v.get_value_for_datastore(self)
                  d[field_name] = self.get_display_value(k, field_value)
              else:
                  if manytomany:
                      field_value = getattr(self, v._lazy_value(), [])
                      d[k] = getattr(self, v._lazy_value(), [])
                      d[field_name] = u', '.join([unicode(x) in field_value])
          return d
docs: Create display dict for instance of Model
          :param fields:
          :param manytomany:
          :param dicttype:
          :param prefix: add prefix to fieldname, e.g.
              prefix='dis_'
              fieldname = 'name' will become 'dis_name'
          :return: