diff --git a/adafruit_tmp007.py b/adafruit_tmp007.py
index 974c070..06b7fcb 100644
--- a/adafruit_tmp007.py
+++ b/adafruit_tmp007.py
@@ -28,6 +28,11 @@
 from micropython import const
 from adafruit_bus_device.i2c_device import I2CDevice
 
+try:
+    from typing_extensions import Literal
+    from busio import I2C
+except ImportError:
+    pass
 
 __version__ = "0.0.0+auto.0"
 __repo__ = "https://github.com/adafruit/Adafruit_CircuitPython_TMP007.git"
@@ -65,15 +70,25 @@ class TMP007:
     # thread safe!
     _BUFFER = bytearray(4)
 
-    def __init__(self, i2c, address=_TMP007_I2CADDR, samplerate=CFG_16SAMPLE):
+    def __init__(
+        self,
+        i2c: I2C,
+        address: int = _TMP007_I2CADDR,
+        samplerate: Literal[
+            CFG_1SAMPLE,
+            CFG_2SAMPLE,
+            CFG_4SAMPLE,
+            CFG_8SAMPLE,
+            CFG_16SAMPLE,
+        ] = CFG_16SAMPLE,
+    ) -> None:
         """Initialize TMP007 device on the specified I2C address and bus number.
         Address defaults to 0x40 and bus number defaults to the appropriate bus
         for the hardware.
         Start taking temperature measurements.  Samplerate can be one of
         TMP007_CFG_1SAMPLE, TMP007_CFG_2SAMPLE, TMP007_CFG_4SAMPLE,
         TMP007_CFG_8SAMPLE, or TMP007_CFG_16SAMPLE.  The default is 16 samples
-        for the highest resolution.  Returns True if the device is intialized,
-        False otherwise.
+        for the highest resolution.
         """
         self._device = I2CDevice(i2c, address)
         self._write_u16(_TMP007_CONFIG, _TMP007_CFG_RESET)
@@ -98,7 +113,7 @@ def __init__(self, i2c, address=_TMP007_I2CADDR, samplerate=CFG_16SAMPLE):
         if dev_id != 0x78:
             raise RuntimeError("Init failed - Did not find TMP007")
 
-    def sleep(self):
+    def sleep(self) -> None:
         """Put TMP007 into low power sleep mode.  No measurement data will be
         updated while in sleep mode.
         """
@@ -106,14 +121,14 @@ def sleep(self):
         control &= ~(_TMP007_CFG_MODEON)
         self._write_u16(_TMP007_CONFIG, control)
 
-    def wake(self):
+    def wake(self) -> None:
         """Wake up TMP007 from low power sleep mode."""
         control = self._read_u16(_TMP007_CONFIG)
         control |= _TMP007_CFG_MODEON
         self._write_u16(_TMP007_CONFIG, control)
 
     @property
-    def raw_voltage(self):
+    def raw_voltage(self) -> int:
         """Read raw voltage from TMP007 sensor.  Meant to be used in the
         calculation of temperature values.
         """
@@ -123,7 +138,7 @@ def raw_voltage(self):
         return raw
 
     @property
-    def raw_sensor_temperature(self):
+    def raw_sensor_temperature(self) -> int:
         """Read raw die temperature from TMP007 sensor.  Meant to be used in the
         calculation of temperature values.
         """
@@ -131,13 +146,13 @@ def raw_sensor_temperature(self):
         return raw >> 2
 
     @property
-    def die_temperature(self):
+    def die_temperature(self) -> float:
         """Read sensor die temperature and return its value in degrees celsius."""
         t_die = self.raw_sensor_temperature
         return t_die * 0.03125
 
     @property
-    def temperature(self):
+    def temperature(self) -> float:
         """Read object temperature from TMP007 sensor."""
         raw = self._read_u16(_TMP007_TOBJ)
         if raw & 1:
@@ -145,29 +160,29 @@ def temperature(self):
         raw = raw >> 2
         return raw * 0.03125
 
-    def read_register(self, register):
+    def read_register(self, register) -> int:
         """Read sensor Register."""
         return self._read_u16(register)
 
-    def _read_u8(self, address):
+    def _read_u8(self, address: int) -> int:
         with self._device as i2c:
             self._BUFFER[0] = address & 0xFF
             i2c.write_then_readinto(self._BUFFER, self._BUFFER, out_end=1, in_end=1)
         return self._BUFFER[0]
 
-    def _read_u16(self, address):
+    def _read_u16(self, address: int) -> int:
         with self._device as i2c:
             self._BUFFER[0] = address & 0xFF
             i2c.write_then_readinto(self._BUFFER, self._BUFFER, out_end=1, in_end=2)
         return self._BUFFER[0] << 8 | self._BUFFER[1]
 
-    def _write_u8(self, address, val):
+    def _write_u8(self, address: int, val: int) -> None:
         with self._device as i2c:
             self._BUFFER[0] = address & 0xFF
             self._BUFFER[1] = val & 0xFF
             i2c.write(self._BUFFER, end=2)
 
-    def _write_u16(self, address, val):
+    def _write_u16(self, address: int, val: int) -> None:
         with self._device as i2c:
             self._BUFFER[0] = address & 0xFF
             self._BUFFER[1] = (val >> 8) & 0xFF
@@ -175,7 +190,7 @@ def _write_u16(self, address, val):
             i2c.write(self._BUFFER, end=3)
 
     @staticmethod
-    def _read_bytes(device, address, count, buf):
+    def _read_bytes(device, address: int, count: int, buf: bytearray) -> None:
         with device as i2c:
             buf[0] = address & 0xFF
             i2c.write_then_readinto(buf, buf, out_end=1, in_end=count)