This is because the Python 3.x variant fails to build:

--8<---------------cut here---------------start------------->8---
======================================================================
FAIL: test_parse_partial_length (pgpdump.test.EncryptedPacketsTestCase)
This file contains an encrypted message with a Partial Body Length header
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/tmp/guix-build-python-pgpdump-1.5.drv-0/pgpdump-1.5/pgpdump/test.py", line 435, in test_parse_partial_length
    rawdata = self.load_data('partial_length.gpg')
  File "/tmp/guix-build-python-pgpdump-1.5.drv-0/pgpdump-1.5/pgpdump/test.py", line 102, in load_data
    self.assertTrue(os.path.exists(full_path))
AssertionError: False is not true

======================================================================
FAIL: test_parse_partial_length (pgpdump.test.EncryptedPacketsTestCase)
This file contains an encrypted message with a Partial Body Length header
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/tmp/guix-build-python-pgpdump-1.5.drv-0/pgpdump-1.5/pgpdump/test.py", line 435, in test_parse_partial_length
    rawdata = self.load_data('partial_length.gpg')
  File "/tmp/guix-build-python-pgpdump-1.5.drv-0/pgpdump-1.5/pgpdump/test.py", line 102, in load_data
    self.assertTrue(os.path.exists(full_path))
AssertionError: False is not true

----------------------------------------------------------------------
Ran 58 tests in 0.546s

FAILED (failures=2)
--8<---------------cut here---------------end--------------->8---

> From ed8ec89c1bd898aa927ddca9c453bc6e950e61a3 Mon Sep 17 00:00:00 2001
> From: ng0 <ng0@infotropique.org>
> Date: Sat, 21 Oct 2017 23:45:51 +0000
> Subject: [PATCH 6/6] gnu: Add python-roca-detect.
>
> * gnu/packages/crypto.scm (python-roca-detect): New variable.

Applied with similar changes as above.

Thank you!

Ludo’.