(use-modules
  (guix packages)
  (guix git-download)
  (gnu packages package-management))

(define conan-1.43 (package
  (inherit conan)
  (version "1.43.0")
  (source
   (origin
     (method git-fetch)               ;no tests in PyPI archive
     (uri (git-reference
           (url "https://github.com/conan-io/conan")
           (commit version)))
     (file-name (git-file-name "conan" version))
     (sha256
      (base32
       "0fd6lr5kvxznyphvylj7j5k80f1h8wam555y5hxmary6vkcyh6pq"))))))

(concatenate-manifests
  (list
    (packages->manifest
      (list
        conan-1.43))
    (specifications->manifest
      '("someotherpackage"))))