<?php
use Microsoft\Graph\Beta\GraphServiceClient;
use Microsoft\Graph\Beta\Generated\Models\UnifiedRoleAssignmentMultiple;
$graphServiceClient = new GraphServiceClient($tokenRequestContext, $scopes);
$requestBody = new UnifiedRoleAssignmentMultiple();
$requestBody->setOdataType('#microsoft.graph.unifiedRoleAssignmentMultiple');
$requestBody->setDisplayName('My test role assignment 1');
$requestBody->setDescription('My role assignment description');
$requestBody->setRoleDefinitionId('b5c08161-a7af-481c-ace2-a20a69a48fb1');
$requestBody->setPrincipalIds(['f8ca5a85-489a-49a0-b555-0a6d81e56f0d', 'c1518aa9-4da5-4c84-a902-a31404023890', ]);
$result = $graphServiceClient->roleManagement()->cloudPC()->roleAssignments()->post($requestBody)->wait();