sudo update-alternatives --config python3
There are 2 choices for the alternative python3 (providing /usr/bin/python3).

  Selection    Path                      Priority   Status
------------------------------------------------------------
* 0            /usr/local/bin/python3.7   50        auto mode
  1            /usr/bin/python3.5         40        manual mode
  2            /usr/local/bin/python3.7   50        manual mode

python3 --version
Python 3.7.3

sudo dpkg -i cython3_0.29.2-2_amd64.deb 
(Reading database ... 128889 files and directories currently installed.)
Preparing to unpack cython3_0.29.2-2_amd64.deb ...
Unpacking cython3 (0.29.2-2) over (0.29.2-2) ...
dpkg: dependency problems prevent configuration of cython3:
 cython3 depends on python3 (>= 3.7~); however:
  Version of python3 on system is 3.5.3-1.

dpkg: error processing package cython3 (--install):
 dependency problems - leaving unconfigured
Errors were encountered while processing:
 cython3

[ -f /usr/bin/yad ]]
+ DIALOG=yad
+ INFO=image=gtk-dialog-info
+ QUESTION=image=gtk-dialog-question
+ WARNING=image=gtk-dialog-warning
+ ERROR=image=gtk-dialog-error
+ BUTTON0=button
+ BUTTON1=button
+ BUTTON0NUM=:0
+ BUTTON1NUM=:1
+ CENTER=--center
+ [[ -n :0.0 ]]
++ id -u
+ [[ 0 -eq 0 ]]
+ PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin
+ check_grub
+ [[ yes = \y\e\s ]]
+ dpkg -l
+ grep '^ii'
+ grep grub-efi-amd64
+ grep -v bin
+ [[ ! -e /var/lib/dpkg/info/dosfstools.list ]]
+ choose_task
+ [[ yes = \y\e\s ]]
+ uefi_message='uefi enabled'
++ yad '--title=Refracta Snapshot 10.2.10 (20191218)' --center --borders=10 --height 400 --width 426 '--text=This utility wil$[/c]

[c]Choose the first option to create a snapshot.[/c]

[c]This is free software that comes with no warranty or guarantee of any type, including but not limited to express, implied, me$
' --button=OK:0 --button=Help:1 --list --column Num --column 'Choose a task' 01 'Create a snapshot (uefi enabled)' 02 'Re-squ$
+ task='01|Create a snapshot (uefi enabled)|'
+ exit_code=0
+ '[' 0 -ne 0 ']'
+ [[ 01|Create a snapshot (uefi enabled)| =~ 01 ]]
+ please_wait
+ yad --image=gtk-dialog-info '--title=Refracta Snapshot' --center '--text=This may take a moment while the program checks fo$
++ pgrep yad
+ wait_pid=2303
+ check_copies
+ [[ -d /home/snapshot ]]
+ ls '/home/snapshot/*.iso'
ls: cannot access '/home/snapshot/*.iso': No such file or directory
+ snapshot_count=0
++ du -sh /home/snapshot
++ awk '{print $1}'
+ snapshot_size=4.0K
+ [[ -z 4.0K ]]
+ [[ -d /home/work/myfs ]]
++ du -sh /home/work/myfs
++ awk '{ print $1 }'
+ saved_size=9.7G
+ saved_copy='* You have a saved copy of the system using 9.7G of space
  located at /home/work/myfs.'
+ [[ no = \y\e\s ]]
+ save_message='* The temporary copy of the filesystem will be created
at /home/work/myfs and removed when this program finishes.'
+ check_directories
++ echo /home/snapshot
++ awk -F / '{ print "/" $2 "/" $3 }'
++ grep /media/
+ snapdir_is_remote=
++ echo /home/work
++ awk -F / '{ print "/" $2 "/" $3 }'
++ grep /media/
+ workdir_is_remote=
+ '[' -n '' ']'
+ '[' -n '' ']'
+ '[' -n '' ']'
+ '[' -n '' ']'
+ [[ -d /home/snapshot ]]
+ [[ no = \n\o ]]
+ [[ -d /home/work ]]
+ rm -rf /home/work
+ mkdir -p /home/work/iso
+ mkdir -p /home/work/myfs
+ check_space
++ df -h -x tmpfs -x devtmpfs -x iso9660 -x udf -x aufs -x squashfs
++ sed 's/Mounted on/Mountpoint/'
++ awk '{ print  $2 "  \t" $3 "  \t" $4 "  \t" $5 "   \t" $6 "   \t\t\t" $1 }'
+ disk_space='Size      Used    Avail   Use%    Mountpoint                      Filesystem
188G    11G     168G    6%      /                       /dev/sda2
511M    5.3M    506M    2%      /boot/efi                       /dev/sda1'
+ check_initrd
+ echo 'Checking initrd.'
+ lsinitramfs /initrd.img
+ grep -q conf.d/cryptroot
+ lsinitramfs /initrd.img
+ grep -q cryptroot/crypttab
+ remove_cryptroot=yes
+ cryptroot_message='The snapshot initrd will be modified to allow booting the unencrypted snapshot.'
+ lsinitramfs /initrd.img
+ egrep -q 'conf.d/resume|conf.d/zz-resume-auto'
+ remove_resume=yes
+ swap_message='The snapshot initrd will be modified to allow booting without the host'\''s swap partition.'
+ '[' '' = yes ']'
+ kill 2303
+ report_space
++ mktemp /tmp/snapshot-report.XXXX
+ tempfile=/tmp/snapshot-report.RXju
+ echo '
You will need plenty of free space. It is recommended that free space (Avail) in the partition that
holds the work directory (probably "/") should be two times the total installed system size (Used).
(Note: You can deduct the space taken up by previous snapshots and any saved copies of the system from the Used amount.)[/c]

[c]Please CLOSE any running applications NOW.
Turn off NUM LOCK for some laptops.[/c]

[c]* You have 0 snapshots taking up 4.0K of disk space.
* You have a saved copy of the system using 9.7G of space
  located at /home/work/myfs.
* The temporary copy of the filesystem will be created
at /home/work/myfs and removed when this program finishes.
* The snapshot directory is currently set to /home/snapshot[/c]

[c]You can change these and other settings by editing
/etc/refractasnapshot.conf.[/c]

[c]The snapshot initrd will be modified to allow booting the unencrypted snapshot.
The snapshot initrd will be modified to allow booting without the host'\''s swap partition.
Current disk usage:
(For complete listing, exit and run '\''df -h'\'')[/c]

[c]Size    Used    Avail   Use%    Mountpoint                      Filesystem
188G    11G     168G    6%      /                       /dev/sda2
511M    5.3M    506M    2%      /boot/efi                       /dev/sda1'
+ yad --text-info '--title=Status Report' --center --height 400 --width 700 --button=OK:0 --button=Exit:1
+ exit_code=0
+ '[' 0 -ne 0 ']'
+ rm -f /tmp/snapshot-report.RXju
+ set_distro_name
+ [[ /usr/lib/refractasnapshot/iso = \/\u\s\r\/\l\i\b\/\r\e\f\r\a\c\t\a\s\n\a\p\s\h\o\t\/\i\s\o ]]
+ [[ live.cfg = \l\i\v\e\.\c\f\g ]]
++ lsb_release -i -s
+ DISTRO=Debian
++ grep -q Refracta /etc/issue
++ yad --entry '--title=Linux Distribution' --center '--text=This is the distribution name that will appear in the boot menu
for the live image. If it'\''s blank, the menu entries will just say
"GNU/Linux (kernel-version)" ' --entry-text=Debian --width=500 --button=OK:0
+ DISTRO=Debian
+ [[ -z Debian ]]
+ housekeeping
+ [[ '' = \y\e\s ]]
+ [[ -n '' ]]
++ awk -F: '/1000:1000/ { print $1 }' /etc/passwd
+ username=rich
+ [[ rich != user ]]
+ username_opt=username=rich
+ [[ no = \y\e\s ]]
+ [[ -e /vmlinuz ]]
+ [[ -e /initrd.img ]]
+ [[ -n '' ]]
+ [[ -n '' ]]
+ [[ yes = \y\e\s ]]
+ updatedb
/usr/bin/refractasnapshot-gui: line 795: updatedb: command not found
+ tee /dev/fd/63
++ yad '--title=Running updatedb...' --center --progress --pulsate --auto-close --width 300
+ [[ '' = \y\e\s ]]
+ cd /home/work
+ copy_isolinux
+ [[ -f /usr/lib/ISOLINUX/isolinux.bin ]]
+ isolinuxbin=/usr/lib/ISOLINUX/isolinux.bin
+ [[ -f /usr/lib/syslinux/modules/bios/vesamenu.c32 ]]
+ vesamenu=/usr/lib/syslinux/modules/bios/vesamenu.c32
+ rsync -a /usr/lib/syslinux/modules/bios/chain.c32 /usr/lib/refractasnapshot/iso/isolinux/
+ rsync -a /usr/lib/syslinux/modules/bios/ldlinux.c32 /usr/lib/refractasnapshot/iso/isolinux/
+ rsync -a /usr/lib/syslinux/modules/bios/libcom32.c32 /usr/lib/refractasnapshot/iso/isolinux/
+ rsync -a /usr/lib/syslinux/modules/bios/libutil.c32 /usr/lib/refractasnapshot/iso/isolinux/
+ rsync -a /usr/lib/ISOLINUX/isolinux.bin /usr/lib/refractasnapshot/iso/isolinux/
+ rsync -a /usr/lib/syslinux/modules/bios/vesamenu.c32 /usr/lib/refractasnapshot/iso/isolinux/
+ [[ '' = \y\e\s ]]
+ copy_kernel
+ rsync -a /usr/lib/refractasnapshot/iso/ /home/work/iso/
+ cp /vmlinuz /home/work/iso/live/
+ cp /initrd.img /home/work/iso/live/
+ copy_filesystem
+ [[ no = \y\e\s ]]
+ rsync -av / myfs/ --delete-before --delete-excluded --exclude=/home/work --exclude=/home/snapshot --exclude=/home/work/efi-$
+ tee /dev/fd/63
++ yad '--title=Copying filesystem...' --center --progress --pulsate --auto-close --width 300[/c]

[c](yad:3885): GLib-CRITICAL **: 21:15:24.515: g_source_remove: assertion 'tag > 0' failed
+ [[ -n '' ]]
+ '[' yes = yes ']'
+ clean_initrd
+ extract_initrd
+ mkdir /tmp/extracted
mkdir: cannot create directory ‘/tmp/extracted’: File exists
+ pushd /tmp/extracted
++ file -L /initrd.img
++ egrep -o 'gzip compressed|XZ compressed|cpio archive'
+ COMPRESSION='cpio archive'
+ '[' 'cpio archive' = 'gzip compressed' ']'
+ '[' 'cpio archive' = 'XZ compressed' ']'
+ '[' 'cpio archive' = 'cpio archive' ']'
+ echo 'Archive is cpio archive...'
+ cpio -i
cpio: kernel/x86/microcode/AuthenticAMD.bin not created: newer or same age version exists
62 blocks
+ zcat

dsp.alsa.device=default
mixer.alsa.device=default
mixer.alsa.channel=PCM
output_plugin=alsa