Peter, I manged to do a backtrace using GDB ? makes no sense to me but here it is
gdb --args python CIFAR_10.py
(gdb) run
Starting program: /home/clived/anaconda3/envs/tflow/bin/python CIFAR_10.py
[Thread debugging using libthread_db enabled]
Using host libthread_db library “/lib/x86_64-linux-gnu/libthread_db.so.1”.
Files already downloaded and verified
[New Thread 0x7fffd6fa2780 (LWP 22610)]
Files already downloaded and verified
[New Thread 0x7fffcbf5d700 (LWP 22614)]
[New Thread 0x7fffcb75c700 (LWP 22615)]
[New Thread 0x7fffca315700 (LWP 22620)]
[New Thread 0x7fffb9b79700 (LWP 22621)]
^C
Thread 1 “python” received signal SIGINT, Interrupt.
(gdb) backtrace
#0  0x00007ffff78d9bf9 in _GI___poll (fds=0x7fffc00072d0, nfds=1, timeout=-1) at …/sysdeps/unix/sysv/linux/poll.c:29
#1  0x00007fffd4098cb3 in g_main_context_iterate.isra () from /home/clived/anaconda3/envs/tflow/lib/python3.6/site-packages/PyQt5/…/…/…/./libglib-2.0.so.0
#2  0x00007fffd4098dce in g_main_context_iteration () from /home/clived/anaconda3/envs/tflow/lib/python3.6/site-packages/PyQt5/…/…/…/./libglib-2.0.so.0
#3  0x00007fffd4b608df in QEventDispatcherGlib::processEvents(QFlagsQEventLoop::ProcessEventsFlag) ()
from /home/clived/anaconda3/envs/tflow/lib/python3.6/site-packages/PyQt5/…/…/…/libQt5Core.so.5
#4  0x00007fffd4b30eb7 in QEventLoop::exec(QFlagsQEventLoop::ProcessEventsFlag) ()
from /home/clived/anaconda3/envs/tflow/lib/python3.6/site-packages/PyQt5/…/…/…/libQt5Core.so.5
#5  0x00007fffd4b34aab in QCoreApplication::exec() () from /home/clived/anaconda3/envs/tflow/lib/python3.6/site-packages/PyQt5/…/…/…/libQt5Core.so.5
#6  0x00007fffcc875970 in meth_QApplication_exec () from /home/clived/anaconda3/envs/tflow/lib/python3.6/site-packages/PyQt5/QtWidgets.so
#7  0x0000555555665b91 in _PyCFunction_FastCallDict () at /tmp/build/80754af9/python_1564510748219/work/Objects/methodobject.c:234
#8  0x00005555556edabc in call_function () at /tmp/build/80754af9/python_1564510748219/work/Python/ceval.c:4851
#9  0x000055555571075a in _PyEval_EvalFrameDefault () at /tmp/build/80754af9/python_1564510748219/work/Python/ceval.c:3335
#10 0x00005555556e7c5b in _PyFunction_FastCall (globals=, nargs=0, args=, co=)
at /tmp/build/80754af9/python_1564510748219/work/Python/ceval.c:4933
#11 fast_function () at /tmp/build/80754af9/python_1564510748219/work/Python/ceval.c:4968
#12 0x00005555556edb95 in call_function () at /tmp/build/80754af9/python_1564510748219/work/Python/ceval.c:4872
#13 0x000055555571075a in _PyEval_EvalFrameDefault () at /tmp/build/80754af9/python_1564510748219/work/Python/ceval.c:3335
#14 0x00005555556e89b9 in _PyEval_EvalCodeWithName (qualname=0x0, name=, closure=0x0, kwdefs=0x0, defcount=1, defs=0x7fffd5a47728, kwstep=2,
kwcount=, kwargs=0x7ffff7f9c068, kwnames=0x7ffff7f9c060, argcount=, args=0x5555572f2410, locals=0x0, globals=,
_co=0x7fffd5a489c0) at /tmp/build/80754af9/python_1564510748219/work/Python/ceval.c:4166
#15 PyEval_EvalCodeEx () at /tmp/build/80754af9/python_1564510748219/work/Python/ceval.c:4187
#16 0x00005555556e98e6 in function_call () at /tmp/build/80754af9/python_1564510748219/work/Objects/funcobject.c:604
#17 0x0000555555665a5e in PyObject_Call () at /tmp/build/80754af9/python_1564510748219/work/Objects/abstract.c:2261
—Type  to continue, or q  to quit—
#18 0x0000555555711e37 in do_call_core (kwdict=0x7fffcbf91438, callargs=0x7fffc8f8b0f0, func=0x7fffd5a21a60)
at /tmp/build/80754af9/python_1564510748219/work/Python/ceval.c:5120
#19 _PyEval_EvalFrameDefault () at /tmp/build/80754af9/python_1564510748219/work/Python/ceval.c:3404
#20 0x00005555556e729e in _PyEval_EvalCodeWithName () at /tmp/build/80754af9/python_1564510748219/work/Python/ceval.c:4166
#21 0x00005555556e8598 in _PyFunction_FastCallDict () at /tmp/build/80754af9/python_1564510748219/work/Python/ceval.c:5084
#22 0x000055555566601f in _PyObject_FastCallDict () at /tmp/build/80754af9/python_1564510748219/work/Objects/abstract.c:2310
#23 0x000055555566aaa3 in _PyObject_Call_Prepend () at /tmp/build/80754af9/python_1564510748219/work/Objects/abstract.c:2373
#24 0x0000555555665a5e in PyObject_Call () at /tmp/build/80754af9/python_1564510748219/work/Objects/abstract.c:2261
#25 0x0000555555711e37 in do_call_core (kwdict=0x7fffcbf72480, callargs=0x7ffff7f9c048, func=0x7fffd5504e48)
at /tmp/build/80754af9/python_1564510748219/work/Python/ceval.c:5120
#26 _PyEval_EvalFrameDefault () at /tmp/build/80754af9/python_1564510748219/work/Python/ceval.c:3404
#27 0x00005555556e6e66 in _PyEval_EvalCodeWithName () at /tmp/build/80754af9/python_1564510748219/work/Python/ceval.c:4166
#28 0x00005555556e7ed6 in fast_function () at /tmp/build/80754af9/python_1564510748219/work/Python/ceval.c:4992
#29 0x00005555556edb95 in call_function () at /tmp/build/80754af9/python_1564510748219/work/Python/ceval.c:4872
#30 0x000055555571075a in _PyEval_EvalFrameDefault () at /tmp/build/80754af9/python_1564510748219/work/Python/ceval.c:3335
#31 0x00005555556e7c5b in _PyFunction_FastCall (globals=, nargs=1, args=, co=)
at /tmp/build/80754af9/python_1564510748219/work/Python/ceval.c:4933
#32 fast_function () at /tmp/build/80754af9/python_1564510748219/work/Python/ceval.c:4968
#33 0x00005555556edb95 in call_function () at /tmp/build/80754af9/python_1564510748219/work/Python/ceval.c:4872
#34 0x000055555571075a in _PyEval_EvalFrameDefault () at /tmp/build/80754af9/python_1564510748219/work/Python/ceval.c:3335
#35 0x00005555556e89b9 in _PyEval_EvalCodeWithName (qualname=0x0, name=, closure=0x0, kwdefs=0x0, defcount=0, defs=0x0, kwstep=2, kwcount=,
kwargs=0x0, kwnames=0x0, argcount=0, args=0x0, locals=0x7ffff7f531b0, globals=0x7ffff7f531b0, _co=0x7ffff63f5a50)
at /tmp/build/80754af9/python_1564510748219/work/Python/ceval.c:4166
—Type  to continue, or q  to quit—
#36 PyEval_EvalCodeEx () at /tmp/build/80754af9/python_1564510748219/work/Python/ceval.c:4187
#37 0x00005555556e975c in PyEval_EvalCode (co=co@entry=0x7ffff63f5a50, globals=globals@entry=0x7ffff7f531b0, locals=locals@entry=0x7ffff7f531b0)
at /tmp/build/80754af9/python_1564510748219/work/Python/ceval.c:731
#38 0x0000555555769744 in run_mod () at /tmp/build/80754af9/python_1564510748219/work/Python/pythonrun.c:1025
#39 0x0000555555769b41 in PyRun_FileExFlags () at /tmp/build/80754af9/python_1564510748219/work/Python/pythonrun.c:978
#40 0x0000555555769d43 in PyRun_SimpleFileExFlags () at /tmp/build/80754af9/python_1564510748219/work/Python/pythonrun.c:419
#41 0x0000555555769e4d in PyRun_AnyFileExFlags () at /tmp/build/80754af9/python_1564510748219/work/Python/pythonrun.c:81
#42 0x000055555576d833 in run_file (p_cf=0x7fffffffdc0c, filename=0x5555558a86c0 L"CIFAR_10.py", fp=0x55555593f120)
at /tmp/build/80754af9/python_1564510748219/work/Modules/main.c:340
#43 Py_Main () at /tmp/build/80754af9/python_1564510748219/work/Modules/main.c:811
#44 0x000055555563788e in main () at /tmp/build/80754af9/python_1564510748219/work/Programs/python.c:69
#45 0x00007ffff77e6b97 in __libc_start_main (main=0x5555556377a0 , argc=2, argv=0x7fffffffde18, init=, fini=,
rtld_fini=, stack_end=0x7fffffffde08) at …/csu/libc-start.c:310
#46 0x0000555555717160 in _start () at …/sysdeps/x86_64/elf/start.S:103
(gdb)