Add Missing Type Annotations

adafruit_tca9548a.py

@@ -32,6 +32,14 @@
 import time
 from micropython import const
 
+try:
+    from typing import List
+    from typing_extensions import Literal
+    from circuitpython_typing import WriteableBuffer, ReadableBuffer
+    from busio import I2C
+except ImportError:
+    pass
+
 _DEFAULT_ADDRESS = const(0x70)
 
 __version__ = "0.0.0+auto.0"
@@ -43,35 +51,41 @@ class TCA9548A_Channel:
     of the necessary I2C commands for channel switching. This class needs to
     behave like an I2CDevice."""
 
-    def __init__(self, tca, channel):
+    def __init__(self, tca: "TCA9548A", channel: int) -> None:
         self.tca = tca
         self.channel_switch = bytearray([1 << channel])
 
-    def try_lock(self):
+    def try_lock(self) -> bool:
         """Pass through for try_lock."""
         while not self.tca.i2c.try_lock():
             time.sleep(0)
         self.tca.i2c.writeto(self.tca.address, self.channel_switch)
         return True
 
-    def unlock(self):
+    def unlock(self) -> bool:
         """Pass through for unlock."""
         self.tca.i2c.writeto(self.tca.address, b"\x00")
         return self.tca.i2c.unlock()
 
-    def readfrom_into(self, address, buffer, **kwargs):
+    def readfrom_into(self, address: int, buffer: ReadableBuffer, **kwargs):
         """Pass through for readfrom_into."""
         if address == self.tca.address:
             raise ValueError("Device address must be different than TCA9548A address.")
         return self.tca.i2c.readfrom_into(address, buffer, **kwargs)
 
-    def writeto(self, address, buffer, **kwargs):
+    def writeto(self, address: int, buffer: WriteableBuffer, **kwargs):
         """Pass through for writeto."""
         if address == self.tca.address:
             raise ValueError("Device address must be different than TCA9548A address.")
         return self.tca.i2c.writeto(address, buffer, **kwargs)
 
-    def writeto_then_readfrom(self, address, buffer_out, buffer_in, **kwargs):
+    def writeto_then_readfrom(
+        self,
+        address: int,
+        buffer_out: WriteableBuffer,
+        buffer_in: ReadableBuffer,
+        **kwargs
+    ):
         """Pass through for writeto_then_readfrom."""
         # In linux, at least, this is a special kernel function call
         if address == self.tca.address:
@@ -80,23 +94,23 @@ def writeto_then_readfrom(self, address, buffer_out, buffer_in, **kwargs):
             address, buffer_out, buffer_in, **kwargs
         )
 
-    def scan(self):
+    def scan(self) -> List[int]:
         """Perform an I2C Device Scan"""
         return self.tca.i2c.scan()
 
 
 class TCA9548A:
     """Class which provides interface to TCA9548A I2C multiplexer."""
 
-    def __init__(self, i2c, address=_DEFAULT_ADDRESS):
+    def __init__(self, i2c: I2C, address: int = _DEFAULT_ADDRESS) -> None:
         self.i2c = i2c
         self.address = address
         self.channels = [None] * 8
 
-    def __len__(self):
+    def __len__(self) -> Literal[8]:
         return 8
 
-    def __getitem__(self, key):
+    def __getitem__(self, key: Literal[0, 1, 2, 3, 4, 5, 6, 7]) -> "TCA9548A_Channel":
         if not 0 <= key <= 7:
             raise IndexError("Channel must be an integer in the range: 0-7.")
         if self.channels[key] is None:

requirements.txt

@@ -4,3 +4,5 @@
 
 Adafruit-Blinka
 adafruit-circuitpython-busdevice
+adafruit-circuitpython-typing
+typing-extensions~=4.0