Writing and Bulding emacs-weechat package: In procedure url-fetch, Invalid keyword

[b0f0]

Hello Guix !
(This is my first mail to a newsgroup. )
I would like to package the emacs-weechat package.
I run this command in my terminal:

$guix import elpa -a melpa emacs-weechat

I put the output in to a emacs-weechat.scm file
and then I modified the output like this (everything below this line is 
a emacs-weechat.scm):

;;(define-module (gnu packages emacs-weechat)
;;             #:use-module (guix packages)
;;             #:use-module (guix build download)
;;             #:use-module (guix build-system emacs)
;;               #:use-module (gnu packages emacs-xyz))
(use-modules (guix packages)
             (guix download)
             (guix git-download)
             (guix utils)
             (guix build download)
             (guix build-system emacs)
             (gnu packages emacs-xyz))

(package
  (name "emacs-weechat")
  (version "20190520.1551")
  (source
    (origin
      (method url-fetch)
      (uri (string-append
             "http://melpa.org/packages/weechat-";
             version
             ".tar"))
      (sha256
        (base32
          "143bjyrfz37ihmpkrbr668pn0z1017pjzb1d7hmqrr518slg7a"))))
  (build-system emacs-build-system)
  (propagated-inputs
    `(("emacs-s" ,emacs-s)
      ("emacs-tracking" ,emacs-tracking)))
  (home-page "https://github.com/the-kenny/weechat.el";)
  (synopsis "Chat via WeeChat's relay protocol in Emacs")
  (description "This package provides a way to chat via WeeChat's relay 
protocol in Emacs. Please see README.org on how to use it.")
  (license #f))


I read the manual but I am stuck, in terminal I run this comand:
$guix build --file=emacs-weechat.scm

Backtrace:
In guix/store.scm:
   623:10 19 (call-with-store _)
In guix/scripts/build.scm:
   911:26 18 (_ #<store-connection 256.99 16adae0>)
In ice-9/boot-9.scm:
    829:9 17 (catch _ _ #<procedure 2c2df20 at ice-9/boot-9.scm:104…> …)
In guix/ui.scm:
    495:6 16 (_)
In guix/scripts/build.scm:
    876:5 15 (_)
In srfi/srfi-1.scm:
   679:15 14 (append-map _ _ . _)
   592:17 13 (map1 ("x86_64-linux"))
   679:15 12 (append-map _ _ . _)
   592:17 11 (map1 (#<package address@hidden /home/sht…>))
In guix/scripts/build.scm:
   835:18 10 (_ _)
In guix/packages.scm:
   936:16  9 (cache! #<weak-table 297/443> #<package address@hidden> …)
  1255:22  8 (thunk)
  1188:25  7 (bag->derivation #<store-connection 256.99 16adae0> #<…> …)
In srfi/srfi-1.scm:
   592:29  6 (map1 (("emacs" #<package address@hidden gnu/p…>) …))
   592:17  5 (map1 (("source" #<origin "https://melpa.org/packa…>) …))
In ice-9/boot-9.scm:
    829:9  4 (catch srfi-34 #<procedure 4144930 at guix/packages.sc…> …)
In guix/packages.scm:
  1003:18  3 (_)
In guix/store.scm:
  1794:24  2 (run-with-store _ _ #:guile-for-build _ #:system _ # _)
  1667:13  1 (_ _)
In guix/build/download.scm:
    741:0  0 (url-fetch _ _ #:timeout _ #:verify-certificate? _ # _ # …)

guix/build/download.scm:741:0: In procedure url-fetch:
Invalid keyword: #vu8(234 60 170 81 40 57 227 10 79 11 235 203 123 2 8 
31 216 139 140 201 43 207 91 97 60 227 187 236 229 26 36)

Isn't url-fetch provided with 'guix download' module ?


Kind regards,

b0f0