snmptrapd service cannot be enabled on Ubuntu 22.04

After installing the snmptrapd package by running:

apt -y install snmptrapd

you can start snmptrapd successfully:

systemctl start snmptrapd

however, you won't be able to enable the service. When you try to do so, you get the error below:

# systemctl enable snmptrapd
Synchronizing state of snmptrapd.service with SysV service script with /lib/systemd/systemd-sysv-install.
Executing: /lib/systemd/systemd-sysv-install enable snmptrapd
The unit files have no installation config (WantedBy=, RequiredBy=, Also=,
Alias= settings in the [Install] section, and DefaultInstance= for template
units). This means they are not meant to be enabled using systemctl.

Possible reasons for having this kind of units are:
• A unit may be statically enabled by being symlinked from another unit's
  .wants/ or .requires/ directory.
• A unit's purpose may be to act as a helper for some other unit which has
  a requirement dependency on it.
• A unit may be started when needed via activation (socket, path, timer,
  D-Bus, udev, scripted systemctl call, ...).
• In case of template units, the unit is meant to be enabled with some
  instance name specified.

I believe that this is caused by the missing "[Service]" section in the "/usr/lib/systemd/system/snmptrapd.service" file.

Example:

# cat /usr/lib/systemd/system/snmptrapd.service
[Unit]
Description=Simple Network Management Protocol (SNMP) Trap Daemon.

[Service]
Type=notify
User=Debian-snmp
ExecStart=/usr/sbin/snmptrapd -LOw -f udp:162 udp6:162
ExecReload=/bin/kill -HUP $MAINPID

[Unit]
Description=Simple Network Management Protocol (SNMP) Trap Daemon.

[Service]
Type=notify
User=Debian-snmp
ExecStart=/usr/sbin/snmptrapd -LOw -f udp:162 udp6:162
ExecReload=/bin/kill -HUP $MAINPID

This should've been:

[Unit]
Description=Simple Network Management Protocol (SNMP) Trap Daemon.

[Service]
Type=notify
User=Debian-snmp
ExecStart=/usr/sbin/snmptrapd -LOw -f udp:162 udp6:162
ExecReload=/bin/kill -HUP $MAINPID

[Unit]
Description=Simple Network Management Protocol (SNMP) Trap Daemon.

[Service]
Type=notify
User=Debian-snmp
ExecStart=/usr/sbin/snmptrapd -LOw -f udp:162 udp6:162
ExecReload=/bin/kill -HUP $MAINPID

[Install]
WantedBy=multi-user.target

More info:

# cat /etc/*release
DISTRIB_ID=Ubuntu
DISTRIB_RELEASE=22.04
DISTRIB_CODENAME=jammy
DISTRIB_DESCRIPTION="Ubuntu 22.04.1 LTS"
PRETTY_NAME="Ubuntu 22.04.1 LTS"
NAME="Ubuntu"
VERSION_ID="22.04"
VERSION="22.04.1 LTS (Jammy Jellyfish)"
VERSION_CODENAME=jammy
ID=ubuntu
ID_LIKE=debian
HOME_URL="https://www.ubuntu.com/"
SUPPORT_URL="https://help.ubuntu.com/"
BUG_REPORT_URL="https://bugs.launchpad.net/ubuntu/"
PRIVACY_POLICY_URL="https://www.ubuntu.com/legal/terms-and-policies/privacy-policy"
UBUNTU_CODENAME=jammy

# uname -a
Linux test-xi-ubuntu-22 5.15.0-47-generic #51-Ubuntu SMP Thu Aug 11 07:51:15 UTC 2022 x86_64 x86_64 x86_64 GNU/Linux

# dpkg -l | grep snmptrapd
ii libnetsnmptrapd40:amd64 5.9.1+dfsg-1ubuntu2.2 amd64 SNMP (Simple Network Management Protocol) trap library
ii snmptrapd 5.9.1+dfsg-1ubuntu2.2 amd64 Net-SNMP notification receiver