[Tutor] Finding Matplotlib somewhere

[Ken Green]

When running the following portion of a bioyear.py program (dated some 8 
years ago from Python 2 and now trying to run it in Python 3.

Matplotlib was installed by pip and apt-get and verified by pip3 list. 
When typing each of the following lines in python 3 shell command line, 
no error were noted.

from datetime import date
import matplotlib.dates
from pylab import *
from numpy import array,sin,pi
from sys import argv

Traceback (most recent call last):
   File "bioyear.py", line 24, in <module>
     import matplotlib.dates
ImportError: No module named matplotlib.dates

It seems not to find matplotlib anywhere but it was verified by sudo 
apt-get and pip. How can I incorporate it into the program?

TIA, Ken