Wrong 'serial' module present can cause strange errors

[Williangalvani]

The 'serial' package can cause some mistakes. the correct one is 'pyserial'

error in python2:

python2  simplePingExample.py --device /dev/ttyUSB0 --baudrate 115200
Opening /dev/ttyUSB0 at 115200 bps
Failed to open the given serial port
('\t', AttributeError("'module' object has no attribute 'Serial'",))

Python3:

Failed to open the given serial port
	 module 'serial' has no attribute 'Serial'