I installed openpyxl with
openpyxl
$ pip install openpyxl
when I try the command
from openpyxl import Workbook <
from openpyxl import Workbook
I had the same problem solved using instead of pip install :
sudo apt-get install python-openpyxl sudo apt-get install python3-openpyxl
The sudo command also works better for other packages.