Unable to download msmarco-passage-tct_colbert-hnsw in google colab

[oussaidene]

I tried this code in google colab:
from pyserini.dsearch import SimpleDenseSearcher, TctColBertQueryEncoder
encoder = TctColBertQueryEncoder('castorini/tct_colbert-msmarco')
searcher = SimpleDenseSearcher.from_prebuilt_index('msmarco-passage-tct_colbert-hnsw',encoder)

But i get this message:
Attempting to initialize pre-built index msmarco-passage-tct_colbert-hnsw.
Downloading index at https://www.dropbox.com/s/xrsjn38lk3axfdd/dindex-msmarco-passage-tct_colbert-hnsw-20210112-be7119.tar.gz?dl=1...
dindex-msmarco-passage-tct_colbert-hnsw-20210112-be7119.tar.gz: 0.00B [00:00, ?B/s]Unable to download pre-built index at https://www.dropbox.com/s/xrsjn38lk3axfdd/dindex-msmarco-passage-tct_colbert-hnsw-20210112-be7119.tar.gz?dl=1, trying next URL...
Unable to download pre-built index at any known URLs.

I don't have this problem when i use jupyter on my own machine

[oussaidene]

The problem is solved. i didn't install faiss yet!
this instruction solved it:
!pip install faiss-gpu