nvidia-docker2 support for Ubuntu 14.04?

When I try and install nvidia-docker2 on local hardware under Ubuntu 14.04 following the instructions at https://github.com/NVIDIA/nvidia-docker#quickstart I run into the following:

$ sudo aptitude install nvidia-docker2
The following NEW packages will be installed:
  libnvidia-container-tools{a} libnvidia-container1{a} libseccomp2{a} nvidia-container-runtime{a} nvidia-container-runtime-hook{a} nvidia-docker2{b}
0 packages upgraded, 6 newly installed, 0 to remove and 32 not upgraded.
Need to get 2,424 kB of archives. After unpacking 10.0 MB will be used.
The following packages have unmet dependencies:
 nvidia-docker2 : Depends: docker-ce (= 18.06.2~ce~3-0~ubuntu) which is a virtual package. or
                           docker-ee (= 18.06.2~ee~3-0~ubuntu) which is a virtual package.
The following actions will resolve these dependencies:

     Keep the following packages at their current version:
1)     nvidia-docker2 [Not Installed]



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How can I get nvidia-docker2 installed?

I needed to follow the instructions at https://docs.docker.com/install/linux/docker-ce/ubuntu/ (apparently my docker install is old), and then:

sudo apt-get install nvidia-docker2 docker-ce=18.06.2~ce~3-0~ubuntu