def to_display(self, fields=None, manytomany=False, dicttype=dict, prefix=''):
        """
        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:
        """
        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
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: