add basic support for mypy type checking

bumble/att.py

@@ -22,9 +22,11 @@
 # -----------------------------------------------------------------------------
 # Imports
 # -----------------------------------------------------------------------------
+from __future__ import annotations
 import struct
 from colors import color
 from pyee import EventEmitter
+from typing import Dict, Type
 
 from bumble.core import UUID, name_or_number
 from bumble.hci import HCI_Object, key_with_value
@@ -197,7 +199,7 @@ class ATT_PDU:
     See Bluetooth spec @ Vol 3, Part F - 3.3 ATTRIBUTE PDU
     '''
 
-    pdu_classes = {}
+    pdu_classes: Dict[int, Type[ATT_PDU]] = {}
     op_code = 0
     name = None
 

bumble/avdtp.py

@@ -15,12 +15,14 @@
 # -----------------------------------------------------------------------------
 # Imports
 # -----------------------------------------------------------------------------
+from __future__ import annotations
 import asyncio
 import struct
 import time
 import logging
 from colors import color
 from pyee import EventEmitter
+from typing import Dict, Type
 
 from .core import (
     BT_ADVANCED_AUDIO_DISTRIBUTION_SERVICE,
@@ -627,7 +629,8 @@ class Message:  # pylint:disable=attribute-defined-outside-init
         RESPONSE_REJECT: 'RESPONSE_REJECT',
     }
 
-    subclasses = {}  # Subclasses, by signal identifier and message type
+    # Subclasses, by signal identifier and message type
+    subclasses: Dict[int, Dict[int, Type[Message]]] = {}
 
     @staticmethod
     def message_type_name(message_type):

bumble/core.py

@@ -15,6 +15,7 @@
 # -----------------------------------------------------------------------------
 # Imports
 # -----------------------------------------------------------------------------
+from __future__ import annotations
 import struct
 
 from .company_ids import COMPANY_IDENTIFIERS
@@ -145,7 +146,7 @@ class UUID:
     '''
 
     BASE_UUID = bytes.fromhex('00001000800000805F9B34FB')
-    UUIDS = []  # Registry of all instances created
+    UUIDS: list[UUID] = []  # Registry of all instances created
 
     def __init__(self, uuid_str_or_int, name=None):
         if isinstance(uuid_str_or_int, int):

bumble/device.py

@@ -15,6 +15,7 @@
 # -----------------------------------------------------------------------------
 # Imports
 # -----------------------------------------------------------------------------
+from __future__ import annotations
 from enum import IntEnum
 import functools
 import json
@@ -22,6 +23,8 @@ import asyncio
 import logging
 from contextlib import asynccontextmanager, AsyncExitStack
 from dataclasses import dataclass
+from typing import ClassVar
+
 from colors import color
 
 from .att import ATT_CID, ATT_DEFAULT_MTU, ATT_PDU
@@ -494,6 +497,7 @@ class Peer:
 # -----------------------------------------------------------------------------
 @dataclass
 class ConnectionParametersPreferences:
+    default: ClassVar[ConnectionParametersPreferences]
     connection_interval_min: int = DEVICE_DEFAULT_CONNECTION_INTERVAL_MIN
     connection_interval_max: int = DEVICE_DEFAULT_CONNECTION_INTERVAL_MAX
     max_latency: int = DEVICE_DEFAULT_CONNECTION_MAX_LATENCY
@@ -833,7 +837,7 @@ def host_event_handler(function):
 # List of host event handlers for the Device class.
 # (we define this list outside the class, because referencing a class in method
 #  decorators is not straightforward)
-device_host_event_handlers = []
+device_host_event_handlers: list[str] = []
 
 
 # -----------------------------------------------------------------------------
@@ -2355,7 +2359,7 @@ class Device(CompositeEventEmitter):
 
         if transport == BT_BR_EDR_TRANSPORT:
             # Create a new connection
-            connection: Connection = self.pending_connections.pop(peer_address)
+            connection = self.pending_connections.pop(peer_address)
             connection.complete(
                 connection_handle, peer_resolvable_address, role, connection_parameters
             )

bumble/gatt.py

@@ -217,7 +217,7 @@ class Service(Attribute):
             uuid.to_pdu_bytes(),
         )
         self.uuid = uuid
-        self.included_services = []
+        # self.included_services = []
         self.characteristics = characteristics[:]
         self.primary = primary
 

bumble/hci.py

@@ -15,11 +15,13 @@
 # -----------------------------------------------------------------------------
 # Imports
 # -----------------------------------------------------------------------------
+from __future__ import annotations
 import struct
 import collections
 import logging
 import functools
 from colors import color
+from typing import Dict, Type
 
 from .core import (
     BT_BR_EDR_TRANSPORT,
@@ -1690,6 +1692,11 @@ class Address:
         RANDOM_IDENTITY_ADDRESS: 'RANDOM_IDENTITY_ADDRESS',
     }
 
+    # Type declarations
+    NIL: Address
+    ANY: Address
+    ANY_RANDOM: Address
+
     # pylint: disable-next=unnecessary-lambda
     ADDRESS_TYPE_SPEC = {'size': 1, 'mapper': lambda x: Address.address_type_name(x)}
 
@@ -1874,7 +1881,7 @@ class HCI_Command(HCI_Packet):
     '''
 
     hci_packet_type = HCI_COMMAND_PACKET
-    command_classes = {}
+    command_classes: Dict[int, Type[HCI_Command]] = {}
 
     @staticmethod
     def command(fields=(), return_parameters_fields=()):
@@ -4020,8 +4027,8 @@ class HCI_Event(HCI_Packet):
     '''
 
     hci_packet_type = HCI_EVENT_PACKET
-    event_classes = {}
-    meta_event_classes = {}
+    event_classes: Dict[int, Type[HCI_Event]] = {}
+    meta_event_classes: Dict[int, Type[HCI_LE_Meta_Event]] = {}
 
     @staticmethod
     def event(fields=()):

bumble/l2cap.py

@@ -15,6 +15,7 @@
 # -----------------------------------------------------------------------------
 # Imports
 # -----------------------------------------------------------------------------
+from __future__ import annotations
 import asyncio
 import logging
 import struct
@@ -22,6 +23,7 @@ import struct
 from collections import deque
 from colors import color
 from pyee import EventEmitter
+from typing import Dict, Type
 
 from .core import BT_CENTRAL_ROLE, InvalidStateError, ProtocolError
 from .hci import (
@@ -184,7 +186,7 @@ class L2CAP_Control_Frame:
     See Bluetooth spec @ Vol 3, Part A - 4 SIGNALING PACKET FORMATS
     '''
 
-    classes = {}
+    classes: Dict[int, Type[L2CAP_Control_Frame]] = {}
     code = 0
     name = None
 

bumble/profiles/device_information_service.py

@@ -17,7 +17,7 @@
 # Imports
 # -----------------------------------------------------------------------------
 import struct
-from typing import Tuple
+from typing import Optional, Tuple
 
 from ..gatt_client import ProfileServiceProxy
 from ..gatt import (
@@ -52,14 +52,14 @@ class DeviceInformationService(TemplateService):
 
     def __init__(
         self,
-        manufacturer_name: str = None,
-        model_number: str = None,
-        serial_number: str = None,
-        hardware_revision: str = None,
-        firmware_revision: str = None,
-        software_revision: str = None,
-        system_id: Tuple[int, int] = None,  # (OUI, Manufacturer ID)
-        ieee_regulatory_certification_data_list: bytes = None
+        manufacturer_name: Optional[str] = None,
+        model_number: Optional[str] = None,
+        serial_number: Optional[str] = None,
+        hardware_revision: Optional[str] = None,
+        firmware_revision: Optional[str] = None,
+        software_revision: Optional[str] = None,
+        system_id: Optional[Tuple[int, int]] = None,  # (OUI, Manufacturer ID)
+        ieee_regulatory_certification_data_list: Optional[bytes] = None
         # TODO: pnp_id
     ):
         characteristics = [

bumble/sdp.py

@@ -15,10 +15,12 @@
 # -----------------------------------------------------------------------------
 # Imports
 # -----------------------------------------------------------------------------
+from __future__ import annotations
 import logging
 import struct
 from colors import color
 import colors
+from typing import Dict, Type
 
 from . import core
 from .core import InvalidStateError
@@ -520,7 +522,7 @@ class SDP_PDU:
     See Bluetooth spec @ Vol 3, Part B - 4.2 PROTOCOL DATA UNIT FORMAT
     '''
 
-    sdp_pdu_classes = {}
+    sdp_pdu_classes: Dict[int, Type[SDP_PDU]] = {}
     name = None
     pdu_id = 0
 

bumble/smp.py

@@ -22,9 +22,12 @@
 # -----------------------------------------------------------------------------
 # Imports
 # -----------------------------------------------------------------------------
+from __future__ import annotations
 import logging
 import asyncio
 import secrets
+from typing import Dict, Type
+
 from pyee import EventEmitter
 from colors import color
 
@@ -184,7 +187,7 @@ class SMP_Command:
     See Bluetooth spec @ Vol 3, Part H - 3 SECURITY MANAGER PROTOCOL
     '''
 
-    smp_classes = {}
+    smp_classes: Dict[int, Type[SMP_Command]] = {}
     code = 0
     name = ''
 

bumble/transport/android_emulator.py

@@ -1,4 +1,4 @@
-# Copyright 2021-2022 Google LLC
+# Copyright 2021-2023 Google LLC
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
@@ -20,9 +20,11 @@ import grpc
 
 from .common import PumpedTransport, PumpedPacketSource, PumpedPacketSink
 from .emulated_bluetooth_pb2_grpc import EmulatedBluetoothServiceStub
-from .emulated_bluetooth_packets_pb2 import HCIPacket
 from .emulated_bluetooth_vhci_pb2_grpc import VhciForwardingServiceStub
 
+# pylint: disable-next=no-name-in-module
+from .emulated_bluetooth_packets_pb2 import HCIPacket
+
 
 # -----------------------------------------------------------------------------
 # Logging

bumble/transport/emulated_bluetooth_packets_pb2.py

@@ -1,4 +1,4 @@
-# Copyright 2021-2022 Google LLC
+# Copyright 2021-2023 Google LLC
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
@@ -16,10 +16,9 @@
 # Generated by the protocol buffer compiler.  DO NOT EDIT!
 # source: emulated_bluetooth_packets.proto
 """Generated protocol buffer code."""
+from google.protobuf.internal import builder as _builder
 from google.protobuf import descriptor as _descriptor
 from google.protobuf import descriptor_pool as _descriptor_pool
-from google.protobuf import message as _message
-from google.protobuf import reflection as _reflection
 from google.protobuf import symbol_database as _symbol_database
 
 # @@protoc_insertion_point(imports)
@@ -31,20 +30,10 @@ DESCRIPTOR = _descriptor_pool.Default().AddSerializedFile(
     b'\n emulated_bluetooth_packets.proto\x12\x1b\x61ndroid.emulation.bluetooth\"\xfb\x01\n\tHCIPacket\x12?\n\x04type\x18\x01 \x01(\x0e\x32\x31.android.emulation.bluetooth.HCIPacket.PacketType\x12\x0e\n\x06packet\x18\x02 \x01(\x0c\"\x9c\x01\n\nPacketType\x12\x1b\n\x17PACKET_TYPE_UNSPECIFIED\x10\x00\x12\x1b\n\x17PACKET_TYPE_HCI_COMMAND\x10\x01\x12\x13\n\x0fPACKET_TYPE_ACL\x10\x02\x12\x13\n\x0fPACKET_TYPE_SCO\x10\x03\x12\x15\n\x11PACKET_TYPE_EVENT\x10\x04\x12\x13\n\x0fPACKET_TYPE_ISO\x10\x05\x42J\n\x1f\x63om.android.emulation.bluetoothP\x01\xf8\x01\x01\xa2\x02\x03\x41\x45\x42\xaa\x02\x1b\x41ndroid.Emulation.Bluetoothb\x06proto3'
 )
 
-
-_HCIPACKET = DESCRIPTOR.message_types_by_name['HCIPacket']
-_HCIPACKET_PACKETTYPE = _HCIPACKET.enum_types_by_name['PacketType']
-HCIPacket = _reflection.GeneratedProtocolMessageType(
-    'HCIPacket',
-    (_message.Message,),
-    {
-        'DESCRIPTOR': _HCIPACKET,
-        '__module__': 'emulated_bluetooth_packets_pb2'
-        # @@protoc_insertion_point(class_scope:android.emulation.bluetooth.HCIPacket)
-    },
+_builder.BuildMessageAndEnumDescriptors(DESCRIPTOR, globals())
+_builder.BuildTopDescriptorsAndMessages(
+    DESCRIPTOR, 'emulated_bluetooth_packets_pb2', globals()
 )
-_sym_db.RegisterMessage(HCIPacket)
-
 if _descriptor._USE_C_DESCRIPTORS == False:
 
     DESCRIPTOR._options = None

bumble/transport/emulated_bluetooth_packets_pb2.pyi

@@ -0,0 +1,41 @@
+# Copyright 2021-2023 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from google.protobuf.internal import enum_type_wrapper as _enum_type_wrapper
+from google.protobuf import descriptor as _descriptor
+from google.protobuf import message as _message
+from typing import ClassVar as _ClassVar, Optional as _Optional, Union as _Union
+
+DESCRIPTOR: _descriptor.FileDescriptor
+
+class HCIPacket(_message.Message):
+    __slots__ = ["packet", "type"]
+
+    class PacketType(int, metaclass=_enum_type_wrapper.EnumTypeWrapper):
+        __slots__ = []
+    PACKET_FIELD_NUMBER: _ClassVar[int]
+    PACKET_TYPE_ACL: HCIPacket.PacketType
+    PACKET_TYPE_EVENT: HCIPacket.PacketType
+    PACKET_TYPE_HCI_COMMAND: HCIPacket.PacketType
+    PACKET_TYPE_ISO: HCIPacket.PacketType
+    PACKET_TYPE_SCO: HCIPacket.PacketType
+    PACKET_TYPE_UNSPECIFIED: HCIPacket.PacketType
+    TYPE_FIELD_NUMBER: _ClassVar[int]
+    packet: bytes
+    type: HCIPacket.PacketType
+    def __init__(
+        self,
+        type: _Optional[_Union[HCIPacket.PacketType, str]] = ...,
+        packet: _Optional[bytes] = ...,
+    ) -> None: ...

bumble/transport/emulated_bluetooth_packets_pb2_grpc.py

@@ -0,0 +1,17 @@
+# Copyright 2021-2023 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# Generated by the gRPC Python protocol compiler plugin. DO NOT EDIT!
+"""Client and server classes corresponding to protobuf-defined services."""
+import grpc

bumble/transport/emulated_bluetooth_pb2.py

@@ -1,4 +1,4 @@
-# Copyright 2021-2022 Google LLC
+# Copyright 2021-2023 Google LLC
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
@@ -16,10 +16,9 @@
 # Generated by the protocol buffer compiler.  DO NOT EDIT!
 # source: emulated_bluetooth.proto
 """Generated protocol buffer code."""
+from google.protobuf.internal import builder as _builder
 from google.protobuf import descriptor as _descriptor
 from google.protobuf import descriptor_pool as _descriptor_pool
-from google.protobuf import message as _message
-from google.protobuf import reflection as _reflection
 from google.protobuf import symbol_database as _symbol_database
 
 # @@protoc_insertion_point(imports)
@@ -34,20 +33,8 @@ DESCRIPTOR = _descriptor_pool.Default().AddSerializedFile(
     b'\n\x18\x65mulated_bluetooth.proto\x12\x1b\x61ndroid.emulation.bluetooth\x1a emulated_bluetooth_packets.proto\"\x19\n\x07RawData\x12\x0e\n\x06packet\x18\x01 \x01(\x0c\x32\xcb\x02\n\x18\x45mulatedBluetoothService\x12\x64\n\x12registerClassicPhy\x12$.android.emulation.bluetooth.RawData\x1a$.android.emulation.bluetooth.RawData(\x01\x30\x01\x12`\n\x0eregisterBlePhy\x12$.android.emulation.bluetooth.RawData\x1a$.android.emulation.bluetooth.RawData(\x01\x30\x01\x12g\n\x11registerHCIDevice\x12&.android.emulation.bluetooth.HCIPacket\x1a&.android.emulation.bluetooth.HCIPacket(\x01\x30\x01\x42\"\n\x1e\x63om.android.emulator.bluetoothP\x01\x62\x06proto3'
 )
 
-
-_RAWDATA = DESCRIPTOR.message_types_by_name['RawData']
-RawData = _reflection.GeneratedProtocolMessageType(
-    'RawData',
-    (_message.Message,),
-    {
-        'DESCRIPTOR': _RAWDATA,
-        '__module__': 'emulated_bluetooth_pb2'
-        # @@protoc_insertion_point(class_scope:android.emulation.bluetooth.RawData)
-    },
-)
-_sym_db.RegisterMessage(RawData)
-
-_EMULATEDBLUETOOTHSERVICE = DESCRIPTOR.services_by_name['EmulatedBluetoothService']
+_builder.BuildMessageAndEnumDescriptors(DESCRIPTOR, globals())
+_builder.BuildTopDescriptorsAndMessages(DESCRIPTOR, 'emulated_bluetooth_pb2', globals())
 if _descriptor._USE_C_DESCRIPTORS == False:
 
     DESCRIPTOR._options = None

bumble/transport/emulated_bluetooth_pb2.pyi

@@ -0,0 +1,26 @@
+# Copyright 2021-2023 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import emulated_bluetooth_packets_pb2 as _emulated_bluetooth_packets_pb2
+from google.protobuf import descriptor as _descriptor
+from google.protobuf import message as _message
+from typing import ClassVar as _ClassVar, Optional as _Optional
+
+DESCRIPTOR: _descriptor.FileDescriptor
+
+class RawData(_message.Message):
+    __slots__ = ["packet"]
+    PACKET_FIELD_NUMBER: _ClassVar[int]
+    packet: bytes
+    def __init__(self, packet: _Optional[bytes] = ...) -> None: ...

bumble/transport/emulated_bluetooth_pb2_grpc.py

@@ -1,4 +1,4 @@
-# Copyright 2021-2022 Google LLC
+# Copyright 2021-2023 Google LLC
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.

bumble/transport/emulated_bluetooth_vhci_pb2.py

@@ -1,4 +1,4 @@
-# Copyright 2021-2022 Google LLC
+# Copyright 2021-2023 Google LLC
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
@@ -16,10 +16,9 @@
 # Generated by the protocol buffer compiler.  DO NOT EDIT!
 # source: emulated_bluetooth_vhci.proto
 """Generated protocol buffer code."""
+from google.protobuf.internal import builder as _builder
 from google.protobuf import descriptor as _descriptor
 from google.protobuf import descriptor_pool as _descriptor_pool
-from google.protobuf import message as _message
-from google.protobuf import reflection as _reflection
 from google.protobuf import symbol_database as _symbol_database
 
 # @@protoc_insertion_point(imports)
@@ -27,15 +26,17 @@ from google.protobuf import symbol_database as _symbol_database
 _sym_db = _symbol_database.Default()
 
 
-import emulated_bluetooth_packets_pb2 as emulated__bluetooth__packets__pb2
+from . import emulated_bluetooth_packets_pb2 as emulated__bluetooth__packets__pb2
 
 
 DESCRIPTOR = _descriptor_pool.Default().AddSerializedFile(
     b'\n\x1d\x65mulated_bluetooth_vhci.proto\x12\x1b\x61ndroid.emulation.bluetooth\x1a emulated_bluetooth_packets.proto2y\n\x15VhciForwardingService\x12`\n\nattachVhci\x12&.android.emulation.bluetooth.HCIPacket\x1a&.android.emulation.bluetooth.HCIPacket(\x01\x30\x01\x42J\n\x1f\x63om.android.emulation.bluetoothP\x01\xf8\x01\x01\xa2\x02\x03\x41\x45\x42\xaa\x02\x1b\x41ndroid.Emulation.Bluetoothb\x06proto3'
 )
 
-
-_VHCIFORWARDINGSERVICE = DESCRIPTOR.services_by_name['VhciForwardingService']
+_builder.BuildMessageAndEnumDescriptors(DESCRIPTOR, globals())
+_builder.BuildTopDescriptorsAndMessages(
+    DESCRIPTOR, 'emulated_bluetooth_vhci_pb2', globals()
+)
 if _descriptor._USE_C_DESCRIPTORS == False:
 
     DESCRIPTOR._options = None

bumble/transport/emulated_bluetooth_vhci_pb2.pyi

@@ -0,0 +1,19 @@
+# Copyright 2021-2023 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import emulated_bluetooth_packets_pb2 as _emulated_bluetooth_packets_pb2
+from google.protobuf import descriptor as _descriptor
+from typing import ClassVar as _ClassVar
+
+DESCRIPTOR: _descriptor.FileDescriptor

bumble/transport/emulated_bluetooth_vhci_pb2_grpc.py

@@ -1,4 +1,4 @@
-# Copyright 2021-2022 Google LLC
+# Copyright 2021-2023 Google LLC
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.

bumble/transport/pyusb.py

@@ -204,7 +204,7 @@ async def open_pyusb_transport(spec):
             await self.sink.stop()
             usb.util.release_interface(self.device, 0)
 
-    usb_find =  usb.core.find
+    usb_find = usb.core.find
     try:
         import libusb_package
     except ImportError:
@@ -215,9 +215,7 @@ async def open_pyusb_transport(spec):
     # Find the device according to the spec moniker
     if ':' in spec:
         vendor_id, product_id = spec.split(':')
-        device = usb_find(
-            idVendor=int(vendor_id, 16), idProduct=int(product_id, 16)
-        )
+        device = usb_find(idVendor=int(vendor_id, 16), idProduct=int(product_id, 16))
     else:
         device_index = int(spec)
         devices = list(

bumble/transport/usb.py

@@ -51,8 +51,12 @@ def load_libusb():
     else:
         if libusb_path := libusb_package.get_library_path():
             logger.debug(f'loading libusb library at {libusb_path}')
-            dll_loader = ctypes.WinDLL if platform.system() == 'Windows' else ctypes.CDLL
-            libusb_dll = dll_loader(str(libusb_path), use_errno=True, use_last_error=True)
+            dll_loader = (
+                ctypes.WinDLL if platform.system() == 'Windows' else ctypes.CDLL
+            )
+            libusb_dll = dll_loader(
+                str(libusb_path), use_errno=True, use_last_error=True
+            )
             usb1.loadLibrary(libusb_dll)