1.  Here is the output of the signal.getsignal test:

[jshelly@gl-build bin]$ ./python3
Python 3.7.4 (default, Jul 15 2019, 10:08:37)
[GCC 8.2.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import signal
>>> signal.getsignal(signal.SIGUSR1)
<Handlers.SIG_DFL: 0>

2.  Here is the output after running the provided script in gdb:

[jshelly@gl-build bin]$ gdb -args ./python3 ~/script.py
GNU gdb (GDB) Red Hat Enterprise Linux 7.6.1-114.el7
Copyright (C) 2013 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.  Type "show copying"
and "show warranty" for details.
This GDB was configured as "x86_64-redhat-linux-gnu".
For bug reporting instructions, please see:
<http://www.gnu.org/software/gdb/bugs/>...
Reading symbols from /sw/arcts/centos7/python/3.7.4/bin/python3.7...done.
(gdb) handle SIGUSR1 nostop
Signal        Stop	Print	Pass to program	Description
SIGUSR1       No	Yes	Yes		User defined signal 1
(gdb) run
Starting program: /sw/arcts/centos7/python/3.7.4/bin/./python3 /home/jshelly/script.py
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib64/libthread_db.so.1".

Program received signal SIGUSR1, User defined signal 1.
Current thread 0x00002aaaaaaf59c0 (most recent call first):
  File "/home/jshelly/script.py", line 12 in <module>

Program received signal SIGUSR1, User defined signal 1.
called True

Program received signal SIGSEGV, Segmentation fault.
0x00002aaaaae88924 in visit_decref (op=0x2aaaaacd3468, data=0x0) at Modules/gcmodule.c:271
271	    if (PyObject_IS_GC(op)) {
Missing separate debuginfos, use: debuginfo-install glibc-2.17-260.el7_6.3.x86_64 nss-softokn-freebl-3.36.0-5.el7_5.x86_64
(gdb) where
#0  0x00002aaaaae88924 in visit_decref (op=0x2aaaaacd3468, data=0x0) at Modules/gcmodule.c:271
#1  0x00002aaaaad92d8d in dict_traverse (op=<optimized out>, visit=0x2aaaaae88920 <visit_decref>, arg=0x0) at Objects/dictobject.c:2987
#2  0x00002aaaaae87b3d in subtract_refs (containers=<optimized out>) at Modules/gcmodule.c:296
#3  collect (generation=generation@entry=2, n_collected=n_collected@entry=0x7fffffffce20,
    n_uncollectable=n_uncollectable@entry=0x7fffffffce28, nofail=nofail@entry=0) at Modules/gcmodule.c:853
#4  0x00002aaaaae891c9 in collect_with_callback (generation=2) at Modules/gcmodule.c:1028
#5  PyGC_Collect () at Modules/gcmodule.c:1573
#6  0x00002aaaaae5e62a in Py_FinalizeEx () at Python/pylifecycle.c:1185
#7  0x00002aaaaae86d58 in pymain_main (pymain=pymain@entry=0x7fffffffcf60) at Modules/main.c:3030
#8  0x00002aaaaae874e9 in _Py_UnixMain (argc=<optimized out>, argv=<optimized out>) at Modules/main.c:3063
#9  0x00002aaaabd843d5 in __libc_start_main () from /lib64/libc.so.6
#10 0x000000000040067e in _start ()
(gdb)