human
Solve the following python programming problem given the following code:
@ gen.coroutine 
def QueryContacts(client, obj_store, user_id, device_id, request) : 
    "Queries contacts for the current user.
  Note: This does not remove duplicate contact entries.  This isn't practical because multiple
  contacts with the same contact_id may be present across multiple range query results.  Multiple
  contacts with the same contact_id should be very uncommon, but are possible.  Because older
  contact rows are returned first, the client may assume the last contact with the same contact_id
  is the correct one." 
    def _MakeContactDict(contact) : 
        'Makes a dict for JSON output from the contact.' 
        c_dict = { 
            'contact_id' : contact.contact_id, 
            'contact_source' : contact.contact_source, 
} 
        util.SetIfNotNone (c_dict, 'name', contact.name) 
        util.SetIfNotNone (c_dict, 'given_name', contact.given_name) 
        util.SetIfNotNone (c_dict, 'family_name', contact.family_name) 
        util.SetIfNotNone (c_dict, 'rank', contact.rank) 
        if ((contact.labels is not None) and (len (contact.labels) > 0)) : 
            c_dict ['labels'] = list (contact.labels) 
identities_list = [] 
        if (contact.identities_properties is not None) : 
            for identity_properties in contact.identities_properties : 
                identity_key = identity_properties [0] 
                identity_dict = { 
                    'identity' : identity_key, 
} 
                util.SetIfNotNone (identity_dict, 'description', identity_properties [1]) 
                util.SetIfNotNone (identity_dict, 'user_id', identity_key_to_user_id_map [Identity.Canonicalize (identity_key)]) 
                identities_list.append (identity_dict) 
c_dict ['identities'] = identities_list 
return c_dict 
start_key = request.get ('start_key', None) 
    limit = request.get ('limit', None) 
    contacts = (yield gen.Task (Contact.RangeQuery, client, hash_key = user_id, range_desc = None, limit = limit, col_names = None, excl_start_key = start_key, scan_forward =...

    
    

    Fix the buggy line: user_ids = [(user_ids.user_id if (identity is not None) else None) for identity in identities]
assistant
#Here is Python program to fix the buggy line: user_ids = [(user_ids.

user_ids = [(identity.user_id if (identity is not None) else None) for identity in identities]