human
Solve the following python programming problem given the following code:
def contribute_to_class(self, cls, name) : 
    super (ElasticField, self).contribute_to_class (cls, name) 
    index = index._meta.db_table 
    doc_type = self.doc_type 
    att_id_name = ('_%s_id' % name) 
    att_cache_name = ('_%s_cache' % name) 
    att_val_name = ('_%s_val' % name) 
    def _get(self) : 
        '
            self is the model instance not the field instance
            ' 
        from django.db import connections 
        elst = connections [self._meta.elst_connection] 
        if ((not hasattr (self, att_cache_name)) and (not getattr (self, att_val_name, None)) and getattr (self, att_id_name, None)) : 
            elst = ES ('http://127.0.0.1:9200/') 
            val = elst.get (index, doc_type, id = getattr (self, att_id_name)).get ('_source', None) 
            setattr (self, att_cache_name, val) 
            setattr (self, att_val_name, val) 
return getattr (self, att_val_name, None) 
def _set(self, val) : 
        '
            self is the model instance not the field instance
            ' 
        if (isinstance (val, basestring) and (not hasattr (self, att_id_name))) : 
            setattr (self, att_id_name, val) 
else : 
            setattr (self, att_val_name, (val or None)) 
setattr (cls, self.attname, property (_get, _set)) 

    
    

    Fix the buggy line: index = index._meta.db_table
assistant
#Here is Python code to fix the buggy line: index = index.

index = cls._meta.db_table