Add function docstring

Author: Tuan Nguyen

adafruit_vc0706.py

@@ -214,15 +214,20 @@ def read_picture_into(self, buf):
         return n
 
     def motion_detected(self):
+        """Read the gesture detection result"""
         self._read_response(self._buffer, len(self._buffer))
         if not self._verify_response(_COMM_MOTION_DETECTED):
-            return  False
+            return False
         return True
 
     def get_motion_detect(self):
+        """Query the gesture detection status"""
         return self._run_command(_COMM_MOTION_STATUS, bytes([0x00]), 6)
 
     def set_motion_detect(self, args):
+        """Set gesture detection status
+        args = 0 to unset, 1 to set
+        """
         return self._run_command(_COMM_MOTION_CTRL, bytes([0x01, args]), 5)
 
     def _run_command(self, cmd, args, resplen, flush=True):