code: private String token(final String home, final String code)
          throws IOException {
          final String uri = new Href(this.github)
              .path(PsGithub.LOGIN).path("oauth").path(PsGithub.ACCESS_TOKEN)
              .toString();
          return new JdkRequest(uri)
              .method("POST")
              .header("Accept", "application/xml")
              .body()
              .formParam("client_id", this.app)
              .formParam("redirect_uri", home)
              .formParam("client_secret", this.key)
              .formParam(PsGithub.CODE, code)
              .back()
              .fetch().as(RestResponse.class)
              .assertStatus(HttpURLConnection.HTTP_OK)
              .as(XmlResponse.class)
              .assertXPath("/OAuth/access_token")
              .xml()
              .xpath("/OAuth/access_token/text()")
              .get(0);
      }
docs: Retrieve Github access token.
  @param home Home of this page
  @param code Github "authorization code"
  @return The token
  @throws IOException If failed