6 files changed, 30 insertions, 7 deletions

diff --git a/glucometerutils/common.py b/glucometerutils/common.py
index 1645c8c..8ffa724 100644
--- a/glucometerutils/common.py
+++ b/glucometerutils/common.py
@@ -12,7 +12,7 @@ import enum
 import textwrap
 
 try:
-    from typing import Text
+    from typing import Sequence, Text
 except:
     pass
 
@@ -37,6 +37,7 @@ class MeasurementMethod(enum.Enum):
 
 
 def convert_glucose_unit(value, from_unit, to_unit):
+    # type: (float, Unit, Unit) -> float
     """Convert the given value of glucose level between units.
 
     Args:
@@ -72,6 +73,7 @@ class GlucoseReading:
             MeasurementMethod)) # type: MeasurementMethod
 
     def get_value_as(self, to_unit):
+        # type: (Unit) -> float
         """Returns the reading value as the given unit.
 
         Args:
@@ -80,6 +82,7 @@ class GlucoseReading:
         return convert_glucose_unit(self.value, Unit.MG_DL, to_unit)
 
     def as_csv(self, unit):
+        # type: (Unit) -> Text
         """Returns the reading as a formatted comma-separated value string."""
         return '"%s","%.2f","%s","%s","%s"' % (
             self.timestamp, self.get_value_as(unit), self.meal.value,
@@ -112,11 +115,11 @@ class MeterInfo:
         the device. It can include hardware and software version.
       native_unit: One of the Unit values to identify the meter native unit.
     """
-    model = attr.ib()
-    serial_number = attr.ib(default='N/A')
-    version_info = attr.ib(default=())
+    model = attr.ib()  # Text
+    serial_number = attr.ib(default='N/A')  # Text
+    version_info = attr.ib(default=())  # Sequence[Text]
     native_unit = attr.ib(
-        default=Unit.MG_DL, validator=attr.validators.in_(Unit))
+        default=Unit.MG_DL, validator=attr.validators.in_(Unit))  # Unit
 
     def __str__(self):
         version_information_string = 'N/A'
diff --git a/glucometerutils/support/freestyle.py b/glucometerutils/support/freestyle.py
index 3770b04..5822d18 100644
--- a/glucometerutils/support/freestyle.py
+++ b/glucometerutils/support/freestyle.py
@@ -16,6 +16,11 @@ import datetime
 import logging
 import re
 
+try:
+    from typing import Iterator, List, Text, Tuple
+except:
+    pass
+
 import construct
 
 from glucometerutils import exceptions
@@ -44,6 +49,7 @@ _MULTIRECORDS_FORMAT = re.compile(
 
 
 def _verify_checksum(message, expected_checksum_hex):
+    # type: (Text, Text) -> None
     """Calculate the simple checksum of the message and compare with expected.
 
     Args:
@@ -94,6 +100,7 @@ class FreeStyleHidDevice(hiddevice.HidDevice):
         pass
 
     def _send_command(self, message_type, command):
+        # type: (int, bytes) -> None
         """Send a raw command to the device.
 
         Args:
@@ -108,6 +115,7 @@ class FreeStyleHidDevice(hiddevice.HidDevice):
         self._write(usb_packet)
 
     def _read_response(self):
+        # type: () -> Tuple[int, bytes]
         """Read the response from the device and extracts it."""
         usb_packet = self._read()
 
@@ -128,6 +136,7 @@ class FreeStyleHidDevice(hiddevice.HidDevice):
         return (message_type, bytes(message_content))
 
     def _send_text_command(self, command):
+        # type: (bytes) -> Text
         """Send a command to the device that expects a text reply."""
         self._send_command(self.TEXT_CMD, command)
 
@@ -162,14 +171,17 @@ class FreeStyleHidDevice(hiddevice.HidDevice):
     # protocol, but not many. Only provide here those that do seep to change
     # between them.
     def _get_version(self):
+        # type: () -> Text
         """Return the software version of the device."""
         return self._send_text_command(b'$swver?').rstrip('\r\n')
 
     def get_serial_number(self):
+        # type: () -> Text
         """Returns the serial number of the device."""
         return self._send_text_command(b'$serlnum?').rstrip('\r\n')
 
     def get_datetime(self):
+        # type: () -> datetime.datetime
         """Gets the date and time as reported by the device.
 
         This is one of the few commands that appear common to many of the
@@ -185,6 +197,7 @@ class FreeStyleHidDevice(hiddevice.HidDevice):
         return datetime.datetime(year + 2000, month, day, hour, minute)
 
     def set_datetime(self, date=datetime.datetime.now()):
+        # type: (datetime.datetime) -> datetime.datetime
         """Sets the date and time of the device."""
 
         # The format used by the FreeStyle devices is not composable based on
@@ -205,6 +218,7 @@ class FreeStyleHidDevice(hiddevice.HidDevice):
         raise NotImplementedError
 
     def _get_multirecord(self, command):
+        # type: (bytes) -> Iterator[List[Text]]
         """Queries for, and returns, "multirecords" results.
 
         Multirecords are used for querying events, readings, history and similar
diff --git a/glucometerutils/support/hiddevice.py b/glucometerutils/support/hiddevice.py
index 07596c2..585882e 100644
--- a/glucometerutils/support/hiddevice.py
+++ b/glucometerutils/support/hiddevice.py
@@ -10,7 +10,7 @@ import logging
 import os
 
 try:
-    from typing import Optional
+    from typing import Optional, Text
 except:
     pass
 
@@ -48,6 +48,7 @@ class HidDevice(object):
     TIMEOUT_MS = None  # type: Optional[int]
 
     def __init__(self, device):
+        # type: (Optional[Text]) -> None
         if None in (self.USB_VENDOR_ID, self.USB_PRODUCT_ID) and not device:
             raise exceptions.CommandLineError(
                 '--device parameter is required, should point to a /dev/hidraw '
@@ -79,12 +80,14 @@ class HidDevice(object):
                     message='Unable to connect to meter: %s.' % e)
 
     def _write(self, report):
+        # type: (bytes) -> None
         """Writes a report to the HID handle."""
 
         if self.handle_.write(report) < 0:
             raise exceptions.CommandError()
 
     def _read(self, size=64):
+        # type: (int) -> bytes
         """Read a report from the HID handle.
 
         This is important as it handles the one incompatible interface between
diff --git a/glucometerutils/support/lifescan.py b/glucometerutils/support/lifescan.py
index 353db4d..4df0b8f 100644
--- a/glucometerutils/support/lifescan.py
+++ b/glucometerutils/support/lifescan.py
@@ -28,6 +28,7 @@ class MalformedCommand(exceptions.InvalidResponse):
 
 
 def crc_ccitt(data):
+  # type: (bytes) -> int
   """Calculate the CRC-16-CCITT with LifeScan's common seed.
 
   Args:
diff --git a/glucometerutils/support/lifescan_binary_protocol.py b/glucometerutils/support/lifescan_binary_protocol.py
index 610b5ea..8b37726 100644
--- a/glucometerutils/support/lifescan_binary_protocol.py
+++ b/glucometerutils/support/lifescan_binary_protocol.py
@@ -28,6 +28,7 @@ _LINK_CONTROL = construct.BitStruct(
 )
 
 def LifeScanPacket(include_link_control):
+    # type: (bool) -> construct.Struct
     if include_link_control:
         link_control_construct = _LINK_CONTROL
     else:
diff --git a/glucometerutils/support/serial.py b/glucometerutils/support/serial.py
index 9d7694d..c46d819 100644
--- a/glucometerutils/support/serial.py
+++ b/glucometerutils/support/serial.py
@@ -10,7 +10,7 @@ __license__ = 'MIT'
 import logging
 
 try:
-    from typing import Text
+    from typing import Optional, Text
 except:
     pass
 
@@ -51,6 +51,7 @@ class SerialDevice(object):
     TIMEOUT = 1  # type: float
 
     def __init__(self, device):
+        # type: (Optional[Text]) -> None
         assert self.BAUDRATE is not None
 
         if not device and self.DEFAULT_CABLE_ID: