Error with python2 and python3 #12

I have the next issue, I've installed the library psutil yet, but when I tried to execute the example the next errors appear.

Python2:
ImportError: No module named psutil
Python3:
ModuleNotFoundError: No module named 'ISStreamer'

import psutil
import time
import ISStreamer.Streamer import Streamer
streamer = Streamer(bucket_name=mybname, bucket_key=mykey, access_key=myakey, debug_level=2)
streamer.log("Message: ", "hi")
cpu_percent = psutil.cpu_percent()
streamer.log("cpu_total", cpu_percent)
streamer.flush()
streamer.close()

any idea what I'am doing wrong or what step I missing?

greetings.