Unified pin checking

Author: ondryaso

pirc522/rfid.py

@@ -48,7 +48,7 @@ def __init__(self, bus=0, device=0, speed=1000000, pin_rst=22,
         self.spi.max_speed_hz = speed
 
         GPIO.setmode(pin_mode)
-        if pin_rst is not None:
+        if pin_rst != 0:
             GPIO.setup(pin_rst, GPIO.OUT)
             GPIO.output(pin_rst, 1)
         GPIO.setup(pin_irq, GPIO.IN, pull_up_down=GPIO.PUD_UP)