Experimentally start adding type annotations, and mypy configs.

This cannot currently be added to CI because the lack of `construct` stubs,
which cause "unsupported left operands" for /-constructed structs.

.gitignore

@@ -1,8 +1,9 @@
+*.egg-info/
 *.pyc
 *~
+.cache
+.mypy_cache/
 /MANIFEST
 /dist/
 __pycache__/
-.cache
 build
-*.egg-info/

glucometerutils/support/freestyle.py

@@ -77,8 +77,8 @@ class FreeStyleHidDevice(hiddevice.HidDevice):
     TEXT_CMD = 0x60
     TEXT_REPLY_CMD = 0x60
 
-    USB_VENDOR_ID = 0x1a61  # Abbott Diabetes Care
-    USB_PRODUCT_ID = None
+    USB_VENDOR_ID = 0x1a61  # type: int  # Abbott Diabetes Care
+    USB_PRODUCT_ID = None  # type: int
 
     def connect(self):
         """Open connection to the device, starting the knocking sequence."""
@@ -103,8 +103,8 @@ def _send_command(self, message_type, command):
         usb_packet = _FREESTYLE_MESSAGE.build(
             {'message_type': message_type, 'command': command})
 
-        logging.debug('Sending packet: %r', usb_packet)
-
+        logging.debug('Sending packet: %r', usb_packet
+)
         self._write(usb_packet)
 
     def _read_response(self):

glucometerutils/support/hiddevice.py

@@ -9,6 +9,11 @@
 import logging
 import os
 
+try:
+    from typing import Optional
+except:
+    pass
+
 from glucometerutils import exceptions
 
 
@@ -33,14 +38,14 @@ class HidDevice(object):
 
     Optional parameters available:
 
-      TIMEOUT_MS: (int, default: NOne) the read timeout in milliseconds, used
+      TIMEOUT_MS: (int, default: None) the read timeout in milliseconds, used
         for hidapi reads only. If -1, hidapi will be provided no timeout.
     """
 
-    USB_VENDOR_ID = None
-    USB_PRODUCT_ID = None
+    USB_VENDOR_ID = None  # type: int
+    USB_PRODUCT_ID = None  # type: int
 
-    TIMEOUT_MS = None
+    TIMEOUT_MS = None  # type: Optional[int]
 
     def __init__(self, device):
         if None in (self.USB_VENDOR_ID, self.USB_PRODUCT_ID) and not device:

glucometerutils/support/serial.py

@@ -9,6 +9,11 @@
 
 import logging
 
+try:
+    from typing import Text
+except:
+    pass
+
 import serial
 
 from glucometerutils import exceptions
@@ -40,10 +45,10 @@ class SerialDevice(object):
 
     """
 
-    BAUDRATE = None
-    DEFAULT_CABLE_ID = None
+    BAUDRATE = None  # type: int
+    DEFAULT_CABLE_ID = None  # type: Text
 
-    TIMEOUT = 1
+    TIMEOUT = 1  # type: float
 
     def __init__(self, device):
         assert self.BAUDRATE is not None

mypy.ini

@@ -0,0 +1,14 @@
+[mypy]
+python_version = 3.7
+
+[mypy-serial]
+ignore_missing_imports = True
+
+[mypy-construct]
+ignore_missing_imports = True
+
+[mypy-hid]
+ignore_missing_imports = True
+
+[mypy-pyscsi.*]
+ignore_missing_imports = True