Update arduino.py

typo on line 313 corrected Melodies of the following lenght, can cause trouble to Melodies of the following length, can cause trouble

Author: hamsolo474

Arduino/arduino.py

@@ -310,7 +310,7 @@ def Melody(self, pin, melody, durations):
  length of melody should be of same
  length as length of duration
 
- Melodies of the following lenght, can cause trouble
+ Melodies of the following length, can cause trouble
  when playing it multiple times.
  board.Melody(9,["C4","G3","G3","A3","G3",0,"B3","C4"],
  [4,8,8,4,4,4,4,4])
@@ -614,4 +614,4 @@ def read(self, adrress):
 returnint(response)
 except:
 return0
-
+