Backup fails 'Could not understand duplicity version.'

[Rod Giles]

Deja Dup Version 37.0
Gnome Version 3.26.2
Fedora 27

deja-dup-37.1-1.fc27.x86_64
duplicity-0.7.16-1.fc27.x86_64

uname -a
Linux echidna-fed-3 4.14.16-300.fc27.x86_64 #1 SMP Wed Jan 31 19:24:27 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux

Output from DEJA_DUP_DEBUG=1 deja-dup --restore | tail -n 1000 > /tmp/deja-dup.log

(org.gnome.DejaDup:8056): Gtk-WARNING **: Allocating size to AssistantBackup 0x55e66c26d1d0 without calling gtk_widget_get_preferred_width/height(). How does the code know the size to allocate?
Traceback (most recent call last):
  File "/usr/bin/duplicity", line 42, in <module>
    import fasteners
ImportError: No module named fasteners
<this appears in console, deja-dup.log is empty (o bytes)>

lshw
Machine Information:
description: Notebook
product: Aspire E5-573 (Aspire E5-573_098A_1_31)
vendor: Acer
version: V3.72
serial: NXMVHEK0595470504E7600
width: 64 bits
capabilities: smbios-2.8 dmi-2.8 smp vsyscall32
configuration:
chassis = notebook
family = BDW
sku = Aspire E5-573_098A_1_31
uuid = 4F59CD38-BF67-4C8A-9421-54AB3A0EC07B

[Michael Terry (mterry)]

File this bug against Fedora please. It looks like they aren't packaging it correctly (duplicity should depend on python-fasteners).