Python ctypes Windows operations - script fails in 64bit interpreter, but works fine in 32bit interpreter

The following piece of code uses only standard libraries, and runs without an error in a 32bit Python 3.6 interpreter, but returns an error in a 64bit one (Windows handle is invalid):

import ctypes, ctypes.wintypes

INVALID_HANDLE_VALUE = -1
DIGCF_PRESENT = 0x00000002
DIGCF_DEVICEINTERFACE = 0x00000010
ERROR_INSUFFICIENT_BUFFER = 122
ERROR_NO_MORE_ITEMS = 259
MAXIMUM_USB_STRING_LENGTH = 255

kernel32 = ctypes.windll.kernel32

setupapi = ctypes.windll.setupapi
SetupDiGetClassDevs = setupapi.SetupDiGetClassDevsW
SetupDiEnumDeviceInterfaces = setupapi.SetupDiEnumDeviceInterfaces
SetupDiGetDeviceInterfaceDetail = setupapi.SetupDiGetDeviceInterfaceDetailW

CM_Get_Parent = setupapi.CM_Get_Parent
CM_Get_Device_ID = setupapi.CM_Get_Device_IDW
CM_Request_Device_Eject = setupapi.CM_Request_Device_EjectW

class GUID(ctypes.Structure):
    _fields_ = [("Data1", ctypes.c_ulong),
                ("Data2", ctypes.c_ushort),
                ("Data3", ctypes.c_ushort),
                ("Data4", ctypes.c_ubyte * 8)]

    def __str__(self):
        return '{%08X-%04X-%04X-%04X-%012X}' % (
            self.Data1, self.Data2, self.Data3,
            self.Data4[0] * 256 + self.Data4[1],
            self.Data4[2] * (256 ** 5) +
            self.Data4[3] * (256 ** 4) +
            self.Data4[4] * (256 ** 3) +
            self.Data4[5] * (256 ** 2) +
            self.Data4[6] * 256 +
            self.Data4[7])

class SP_DEVINFO_DATA(ctypes.Structure):
    _fields_ = [("cbSize", ctypes.wintypes.DWORD),
            ("ClassGuid", GUID),
            ("DevInst", ctypes.wintypes.DWORD),
            ("Reserved", ctypes.c_void_p)
            ]

class SP_DEVICE_INTERFACE_DATA(ctypes.Structure):
    _fields_ = [("cbSize", ctypes.wintypes.DWORD),
            ("InterfaceClassGuid", GUID),
            ("Flags", ctypes.wintypes.DWORD),
            ("Reserved", ctypes.c_void_p)
            ]

class SP_DEVICE_INTERFACE_DETAIL_DATA(ctypes.Structure):
    _fields_ = [("cbSize", ctypes.wintypes.DWORD),
            ("DevicePath", ctypes.c_wchar*255)]

GUID_DEVINTERFACE_VOLUME = GUID(0x53F5630D, 0xB6BF, 0x11D0,
        (ctypes.c_ubyte*8)(0x94, 0xF2, 0x00, 0xA0, 0xC9, 0x1E, 0xFB, 0x8B))

hDevInfo = SetupDiGetClassDevs(ctypes.byref(GUID_DEVINTERFACE_VOLUME),
                               0,
                               0,
                               DIGCF_PRESENT | DIGCF_DEVICEINTERFACE)
if hDevInfo == INVALID_HANDLE_VALUE:
    print(ctypes.windll.GetLastError(), ctypes.windll.FormatError())


def get_device_interface(i, device=None):
    interfaceData = SP_DEVICE_INTERFACE_DATA()
    interfaceData.cbSize = ctypes.sizeof(SP_DEVICE_INTERFACE_DATA)
    if SetupDiEnumDeviceInterfaces(
        hDevInfo,
        device and ctypes.byref(device) or None,
        ctypes.byref(GUID_DEVINTERFACE_VOLUME),
        i,
        ctypes.byref(interfaceData)):
        return interfaceData
    elif ctypes.GetLastError() == ERROR_NO_MORE_ITEMS:
        return
    else:
        print(ctypes.GetLastError(), ctypes.FormatError())

def connected_devices():
    interface_index = 0
    interface = get_device_interface(interface_index)

devices  = connected_devices()

I suspect that the issue is not strictly a Python problem, but rather a difference in how 64 and 32 bit interpreter types interact with Windows.

Can anyone explain why this is happening?