ı am using emacs in manjaro linux and ı got error like this ```Error while verifying signature archive-contents.sig:``` when ı install jedi with M-x shortcut 
ı am looking at to this url <https://emacs.stackexchange.com/questions/233/how-to-proceed-on-package-el-signature-check-failure> but ı can not install **gnu-elpa-keyring-update** package because when ı write ```gnu-elpa-TAB``` M-x gives [No match]

package-archives values is:
```
package-archives is a variable defined in ‘package.el’.

Its value is
(("gnu" . "https://elpa.gnu.org/packages/")
 ("nongnu" . "https://elpa.nongnu.org/nongnu/")
 ("melpa" . "https://melpa.org/packages/"))
Original value was 
(("gnu" . "https://elpa.gnu.org/packages/")
 ("nongnu" . "https://elpa.nongnu.org/nongnu/"))

An alist of archives from which to fetch.
The default value points to the GNU Emacs package repository.

Each element has the form (ID . LOCATION).
 ID is an archive name, as a string.
 LOCATION specifies the base location for the archive.
  If it starts with "http(s):", it is treated as an HTTP(S) URL;
  otherwise it should be an absolute directory name.
  (Other types of URL are currently not supported.)

Only add locations that you trust, since fetching and installing
a package can run arbitrary code.

HTTPS URLs should be used where possible, as they offer superior
security.

  This variable may be risky if used as a file-local variable.
  This variable was introduced, or its default value was changed, in
  version 28.1 of Emacs.
  You can customize this variable.
```
init file is:
```
(require 'package)
(add-to-list 'package-archives '("melpa" . "https://melpa.org/packages/") t)

(package-initialize)
(custom-set-variables
 '(package-selected-packages '(jedi)))
(custom-set-faces
```
there is comment lines but ı dont add them into here

ı have /tmo/foo.el file what contains this codes

```
(require 'package)
(add-to-list 'package-archives '("melpa" . "https://melpa.org/packages/") t)
```

and ı open emacs with this codes
```
emacs -Q -l /tmp/foo.el
```
and ı write this codes in my terminal 
```
curl -X GET https://elpa.gnu.org/packages/ | grep gnu-elpa                             
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
  0     0    0     0    0     0      0      0 --:--:--  0:00:02 --:--:--     0<tr><td><a href="gnu-elpa.html">gnu-elpa</a></td><td>1.1</td><td>Advertize GNU ELPA packages</td></tr>
<tr><td><a href="gnu-elpa-keyring-update.html">gnu-elpa-keyring-update</a></td><td>2019.3</td><td>Update Emacs's GPG keyring for GNU ELPA</td></tr>
100 44535  100 44535    0     0  11322      0  0:00:03  0:00:03 --:--:-- 11323

```

and ı open again my emacs with emacs -Q -l
```
M-x package-install RET gnu-elpa
```

and nothing changed

**this paragraph was answer because of ı installed gnu-elpa-keyring-update but ı have still same problem ı copied my answer to here**
* ı remove emacs and foo.el and .emacs files and reinstall emacs 
* ı typed ALT key with SHIFT + : (so ı mean M-: ) and ı write (setq package-check-signature nil) 
* ı dont close emacs and ı type M-x package-install RET gnu-elpa-keyring-update

so gnu-elpa-keyring-update is installed, now there is no problem. 
thanks for take care of with my question for 5 days to 'NickD'

F* still ı have same problem