Can not install musescore-nightly through ppa:mscore-ubuntu/mscore-nightly

sudo add-apt-repository ppa:mscore-ubuntu/mscore-nightly
sudo add-apt-repository ppa:mscore-ubuntu/mscore-stable
sudo apt-get update
sudo apt-get install musescore-nightly

cc@CC:~$ sudo apt-get install musescore-nightly
[sudo] password for cc:
Reading package lists... Done
Building dependency tree
Reading state information... Done
E: Unable to locate package musescore-nightly
cc@CC:~$

cc@CC:~$ sudo apt search musescore
Sorting... Done
Full Text Search... Done
musescore/yakkety,now 2.0.3+dfsg1-2build1~1 amd64 [installed]
Free music composition and notation software

musescore-common/yakkety,yakkety,now 2.0.3+dfsg1-2build1~1 all [installed,automatic]
Free music composition and notation software (common files)

musescore-soundfont-gm/yakkety,yakkety,now 2.0.3+dfsg1-2build1~1 all [installed,automatic]
Old MuseScore soundfont (dummy package)

timgm6mb-soundfont/yakkety,yakkety,now 1.3-2 all [installed,automatic]
TimGM6mb SoundFont from MuseScore 1.3

cc@CC:~$

Q1:no where find any musescore-nightly pacage but the old one (musescore), but it's certain that
https://launchpad.net/~mscore-ubuntu/+archive/ubuntu/mscore-nightly
do have a release of 16.10 so what's wrong with the software and the ppa????
how to slove it????