Watchdog module not found after installing the watchdog package in Ubuntu

[jasmine22]

Hello,
I am new to ubuntu.
Currently I would like to use watchdog package for python script to run in Ubuntu 16.04.1.
So I install watchdog package using the following comment:
sudo apt-get install watchdog
Then, I received this message:
Reading package lists... Done
Building dependency tree
Reading state information... Done
watchdog [COLOR=var(--highlight-keyword)]is[/COLOR] already the newest version ([COLOR=var(--highlight-namespace)]5.14[/COLOR]-3ubuntu0[COLOR=var(--highlight-namespace)].16[/COLOR][COLOR=var(--highlight-namespace)].04[/COLOR][COLOR=var(--highlight-namespace)].1[/COLOR]).
[COLOR=var(--highlight-namespace)]0[/COLOR] upgraded, [COLOR=var(--highlight-namespace)]0[/COLOR] newly installed, [COLOR=var(--highlight-namespace)]0[/COLOR] to remove [COLOR=var(--highlight-keyword)]and[/COLOR] [COLOR=var(--highlight-namespace)]485[/COLOR] [COLOR=var(--highlight-keyword)]not[/COLOR] upgraded.
Then I reboot the ubuntu.
When I check is the package installed successfully by using the following comment:
apt list --installed
However, I don't find watchdog package is installed.

Before installing the watchdog, I also upgrade the packages by using the following comment:
sudo apt-get update
However, I got this messages:

Fetched 6,704 kB in 58s (114 kB/s)

Reading package lists... Done

E: Failed to fetch http://security.ubuntu.com/ubuntu/di...cons-64x64.tar Could not open file /var/lib/apt/lists/partial/security.ubuntu.com_ubuntu_dists_xenial-security_main_dep11_icons-64x64.tar.gz - open (13: Permission denied)

E: Failed to fetch http://sg.archive.ubuntu.com/ubuntu/...cons-64x64.tar Could not open file /var/lib/apt/lists/partial/sg.archive.ubuntu.com_ubuntu_dists_xenial-updates_main_dep11_icons-64x64.tar.gz - open (13: Permission denied)

E: Failed to fetch http://sg.archive.ubuntu.com/ubuntu/...cons-64x64.tar Could not open file /var/lib/apt/lists/partial/sg.archive.ubuntu.com_ubuntu_dists_xenial-backports_main_dep11_icons-64x64.tar.gz - open (13: Permission denied)

E: Some index files failed to download. They have been ignored, or old ones used instead.

May I know how can I install watchdog package in ubuntu ?
Thank you

[QIII]

Hello!

16.04 has passed its end of standard support. It is currently only supported if you are paying for extended support. If you are not, then it would be best to install a currently supported release. Using a release that is out of support is dangerous because you are no longer getting security updates.

[jasmine22]

May I know how can I install a currently supported release?

[him610]

With LTS 20.04.4:

sudo apt install watchdog

Description: system health checker and software/hardware watchdog handler
The watchdog program writes to /dev/watchdog every ten seconds. If
the device is opened but not written to within a minute, the machine
will reboot. This feature is available when the kernel is built with
"software watchdog" support (standard in Debian kernels) or if the
machine is equipped with a hardware watchdog (in which case this
package can also be used to "pet" it, resetting its timer).
.
The kernel software watchdog's ability to reboot will depend on the
state of the machine and interrupts.
.
The watchdog tool itself runs several health checks and acts
appropriately if the system is not in good shape.