code: public ModelNode getSecureIdentitySecurityDomainModuleOptions(String securityDomainName) throws Exception {
  
          Address addr = Address.root().add(SUBSYSTEM, SUBSYSTEM_SECURITY, SECURITY_DOMAIN, securityDomainName,
                  AUTHENTICATION, CLASSIC);
  
          ModelNode authResource = readResource(addr);
          List<ModelNode> loginModules = authResource.get(LOGIN_MODULES).asList();
          for (ModelNode loginModule : loginModules) {
              if ("SecureIdentity".equals(loginModule.get(CODE).asString())) {
                  ModelNode moduleOptions = loginModule.get(MODULE_OPTIONS);
                  return moduleOptions;
              }
          }
  
          return null;
      }
docs: Given the name of an existing security domain that uses the SecureIdentity authentication method,
  this returns the module options for that security domain authentication method. This includes
  the username and password of the domain.
  
  @param securityDomainName the name of the security domain whose module options are to be returned
  @return the module options or null if the security domain doesn't exist
  @throws Exception if the security domain could not be looked up