Last second cleanup of unused variable

Author: makermelissa

adafruit_bitbangio.py

@@ -110,7 +110,6 @@ def __init__(self, scl, sda, *, frequency=400000, timeout=1):
         self._sda.value = 1
 
         self._delay = 1 / frequency / 2
-        self._frequency = frequency
         self._timeout = timeout
 
     def scan(self):
@@ -170,10 +169,12 @@ def _sda_low(self):
 
     def _scl_release(self):
         """Release and let the pullups lift"""
+        # Use self._timeout to add clock stretching
         self._scl.value = 1
 
     def _sda_release(self):
         """Release and let the pullups lift"""
+        # Use self._timeout to add clock stretching
         self._sda.value = 1
 
     def _set_values(self, *, scl, sda, delay=None):