I want to use python-OP_RETURN library.
For this I need to install bitcoin core.
But when I exceute this command
sudo apt-get update I have this error :
Err http://ppa.launchpad.net jessie/main amd64 Packages
Err http://ppa.launchpad.net jessie/main amd64 Packages
Err http://ppa.launchpad.net jessie/main amd64 Packages
Err http://ppa.launchpad.net jessie/main amd64 Packages
Err http://ppa.launchpad.net jessie/main amd64 Packages
404 Not Found
Get:2 http://security.debian.org jessie/updates/main amd64 Packages [371 kB]
Ign http://httpredir.debian.org jessie InRelease
Get:3 http://httpredir.debian.org jessie-updates InRelease [142 kB]
Hit http://httpredir.debian.org jessie Release.gpg
Hit http://httpredir.debian.org jessie Release
Get:4 http://httpredir.debian.org jessie-updates/main amd64 Packages [17.6 kB]
Get:5 http://httpredir.debian.org jessie/main amd64 Packages [9032 kB]
Fetched 9626 kB in 8s (1085 kB/s)
W: Failed to fetch http://ppa.launchpad.net/bitcoin/bitcoin/ubuntu/dists/jessie/main/binary-amd64/Packages 404 Not Found
E: Some index files failed to download. They have been ignored, or old ones used instead.
What does it mean?
