Unsupported GNU version! gcc versions later than 6 are not supported! - causes importing cpp_extension
Then I import it says before error this:

/home/dex/anaconda3/lib/python3.6/site-packages/torch/utils/cpp_extension.py:118: UserWarning: 

                               !! WARNING !!

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Your compiler (c++) may be ABI-incompatible with PyTorch!
Please use a compiler that is ABI-compatible with GCC 4.9 and above.
See https://gcc.gnu.org/onlinedocs/libstdc++/manual/abi.html.

See https://gist.github.com/goldsborough/d466f43e8ffc948ff92de7486c5216d6
for instructions on how to install GCC 4.9 or higher.
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

                              !! WARNING !!

  warnings.warn(ABI_INCOMPATIBILITY_WARNING.format(compiler))


But following gist  trying to install 4.9 and 5.9 same errors
Cant get installed, also on 18.04 but with other error:

  dex@dexpc:~$ sudo apt-get install software-properties-common
[sudo] password for dex: 
Reading package lists... Done
Building dependency tree       
Reading state information... Done
software-properties-common is already the newest version (0.96.24.32.4).
0 upgraded, 0 newly installed, 0 to remove and 2 not upgraded.
dex@dexpc:~$ sudo apt-get update
Ign:1 http://dl.google.com/linux/chrome/deb stable InRelease
Hit:2 http://archive.ubuntu.com/ubuntu bionic InRelease                        
Get:3 http://security.ubuntu.com/ubuntu xenial-security InRelease [107 kB]     
Hit:4 http://ppa.launchpad.net/graphics-drivers/ppa/ubuntu bionic InRelease    
Hit:5 http://dl.google.com/linux/chrome/deb stable Release                     
Hit:6 http://ppa.launchpad.net/noobslab/apps/ubuntu bionic InRelease           
Hit:7 https://download.docker.com/linux/ubuntu bionic InRelease                
Hit:8 http://us.archive.ubuntu.com/ubuntu xenial InRelease                     
Hit:9 http://ppa.launchpad.net/teejee2008/ppa/ubuntu bionic InRelease          
Get:10 http://us.archive.ubuntu.com/ubuntu xenial-updates InRelease [109 kB]   
Hit:11 http://ppa.launchpad.net/ubuntu-toolchain-r/test/ubuntu bionic InRelease
Ign:13 http://ppa.launchpad.net/upubuntu-com/ppa/ubuntu bionic InRelease       
Err:14 http://ppa.launchpad.net/upubuntu-com/ppa/ubuntu bionic Release         
  404  Not Found [IP: 91.189.95.83 80]
Reading package lists... Done                                                  
E: The repository 'http://ppa.launchpad.net/upubuntu-com/ppa/ubuntu bionic Release' does not have a Release file.
N: Updating from such a repository can't be done securely, and is therefore disabled by default.
N: See apt-secure(8) manpage for repository creation and user configuration details.
dex@dexpc:~$ sudo apt-get install gcc-5.9 g++-5.9
Reading package lists... Done
Building dependency tree       
Reading state information... Done
E: Unable to locate package gcc-5.9
E: Couldn't find any package by glob 'gcc-5.9'
E: Couldn't find any package by regex 'gcc-5.9'
E: Unable to locate package g++-5.9
E: Couldn't find any package by glob 'g++-5.9'
E: Couldn't find any package by regex 'g++-5.9'




dex@dexpc:~$ gcc --version
gcc (Ubuntu 7.3.0-16ubuntu3) 7.3.0


Two steps to fix the problem:

1)
There should be a copy of sources.list at  /usr/share/doc/apt/examples/sources.list   Copy your /etc/apt/sources.list to save the ppa changes you entered and start with the fresh copy.  Then run the  

sudo apt-get update
sudo apt-get dist-upgrade


Then add in your ppas from your saved copy of sources list, and repeat the  

sudo apt-get update
sudo apt-get dist-upgrade  


Just in case, here's the contents of the fresh file:  

# See sources.list(5) manpage for more information
# Remember that CD-ROMs, DVDs and such are managed through the apt-cdrom tool.
deb http://us.archive.ubuntu.com/ubuntu xenial main restricted
deb-src http://us.archive.ubuntu.com/ubuntu xenial main restricted

deb http://security.ubuntu.com/ubuntu xenial-security main restricted
deb-src http://security.ubuntu.com/ubuntu xenial-security main restricted

deb http://us.archive.ubuntu.com/ubuntu xenial-updates main restricted
deb-src http://us.archive.ubuntu.com/ubuntu xenial-updates main restricted


2) To get rif off obsolete ppa

sudo apt-add-repository -r ppa:armagetronad-dev/ppa 
sudo apt update -q

