Problem With Tkinter Font

[Wildman]

Python 3.4.2
Tkinter 8.6
Linux

I want to set the font in a GUI program I am working on.
Here is the pertinent code I am using...

from tkinter import font

myfont = font.Font(family='Helvetica', size=10, weight='bold')

Here is the error I get...

Traceback (most recent call last):
  File "./test.py", line 41, in <module>
    myfont = font.Font(family='Helvetica', size=10, weight="bold")
  File "/usr/lib/python3.4/tkinter/font.py", line 93, in __init__
    tk.call("font", "create", self.name, *font)
AttributeError: 'NoneType' object has no attribute 'call'

>From my research, the syntax is correct but I am having
doubts.  Can anyone clarify?

-- 
<Wildman> GNU/Linux user #557453
The cow died so I don't need your bull!