C:\Python37-32\python.exe E:/PYTHON_SKETCH/Led13.py
Traceback (most recent call last):
  File "E:/PYTHON_SKETCH/Led13.py", line 4, in <module>
    board = pyfirmata.Arduino("COM3")
  File "C:\Python37-32\lib\site-packages\pyfirmata\__init__.py", line 19, in __init__
    super(Arduino, self).__init__(*args, **kwargs)
  File "C:\Python37-32\lib\site-packages\pyfirmata\pyfirmata.py", line 89, in __init__
    self.sp = serial.Serial(port, baudrate, timeout=timeout)
AttributeError: module 'serial' has no attribute 'Serial' 

  import pyfirmata
import time
board = pyfirmata.Arduino("COM3")
it = pyfirmata.util.Iterator(board)
it.start()
board.digital[10].mode = pyfirmata.INPUT
while True:
    sw = board.digital[10].read()
    if sw is True:
        board.digital[13].write(1)
    else:
        board.digital[13].write(0)
    time.sleep(0.1) 

  
import serial
serial.Serial

  
>>> import serial
>>> serial.Serial
<class 'serial.serialposix.Serial'>
>>>

  import serial
serial.Serial
Traceback (most recent call last):
  File "<input>", line 1, in <module>
AttributeError: module 'serial' has no attribute 'Serial'   

  from pyfirmata import Arduino, util
import time
board = Arduino("COM4")
loopTimes = input('How many times would you like the LED to blink: ')
print("Blinking " + loopTimes + " times.")
for x in range(int(loopTimes)):
	board.digital[13].write(1)
	time.sleep(0.2)
	board.digital[13].write(0)
	time.sleep(0.2)