Update adafruit_dht.py

Catch the exception raised by blinka.

Author: yeyeto2788

adafruit_dht.py

@@ -31,7 +31,7 @@
 import array
 import time
 from os import uname
-from digitalio import DigitalInOut, Direction
+from digitalio import DigitalInOut, Pull, Direction
 
 _USE_PULSEIO = False
 try:
@@ -160,7 +160,15 @@ def _get_pulses_bitbang(self):
             timestamp = time.monotonic()  # take timestamp
             dhtval = True  # start with dht pin true because its pulled up
             dhtpin.direction = Direction.INPUT
-            dhtpin.pull = None
+
+            try:
+                dhtpin.pull = Pull.UP
+            # Catch the NotImplementedError raised because
+            # blinka.microcontroller.generic_linux.libgpiod_pin does not support
+            # internal pull resistors.
+            except NotImplementedError:
+                dhtpin.pull = None
+
             while time.monotonic() - timestamp < 0.25:
                 if dhtval != dhtpin.value:
                     dhtval = not dhtval  # we toggled