pyvmomi - How to obtain the username and password of the Guest operating system？

User vim.vm.GuestInfo just can get these information

(vmodl.DynamicProperty) {
               name = u'guest',
               val = (vim.vm.GuestInfo) {
                  dynamicType = <unset>,
                  dynamicProperty = (vmodl.DynamicProperty) [],
                  toolsStatus = 'toolsNotInstalled',
                  toolsVersionStatus = 'guestToolsNotInstalled',
                  toolsVersionStatus2 = 'guestToolsNotInstalled',
                  toolsRunningStatus = 'guestToolsNotRunning',
                  toolsVersion = <unset>,
                  toolsInstallType = <unset>,
                  toolsUpdateStatus = <unset>,
                  guestId = 'windows7Server64Guest',
                  guestFamily = <unset>,
                  guestFullName = 'Microsoft Windows Server 2008 R2 (64 \xe4\xbd\x8d)',
                  hostName = <unset>,
                  ipAddress = <unset>,
                  net = (vim.vm.GuestInfo.NicInfo) [],
                  ipStack = (vim.vm.GuestInfo.StackInfo) [],
                  disk = (vim.vm.GuestInfo.DiskInfo) [],
                  screen = (vim.vm.GuestInfo.ScreenInfo) {
                     dynamicType = <unset>,
                     dynamicProperty = (vmodl.DynamicProperty) [],
                     width = -1,
                     height = -1
                  },
                  guestState = 'notRunning',
                  powerPolicy = <unset>,
                  appHeartbeatStatus = <unset>,
                  guestKernelCrashed = <unset>,
                  appState = <unset>,
                  guestOperationsReady = false,
                  interactiveGuestOperationsReady = false,
                  guestStateChangeSupported = false,
                  generationInfo = (vim.vm.GuestInfo.NamespaceGenerationInfo) []
               }
            },

The username and password of the Guest operation system are not included in these information. Can you help me to get the username and password of the Guest operation system?

Start by reading the vim.vm.GuestInfo definition and the pyvmomi or vSphere API documentation relevant to guest operating-system access. Determine whether the requested credentials are represented or exposed by the API; done would be a documented, supported answer or a clear statement of the limitation.