"no display found. Using non-interactive Agg backend" in windows

Describe the bug First of all, great work with the impedance package. When I import Randles from impedance.circuits, it does not let me plot figures using matplotlib. The package is checking environment variable DISPLAY in curcuits.py. I think windows (I am a window user) does not have a DISPLAY environment variable, atleast mine does not. Thats why in circuits.py, line mpl.use('Agg') is executed. There are some potential solutions to check for display in windows in this post

To Reproduce Steps to reproduce the behavior:

1. Code which generates the error

import matplotlib.pyplot as plt
from impedance.circuits import Randles

plt.plot([1, 2, 3, 4])
plt.show()
....

1. Full error info I am getting the following message when I am importing Randles from impedance.circuits.

no display found. Using non-interactive Agg backend
C:\Users\Sumbal\Documents\atom\data-analysis\antranik\controller\controller.py:193: UserWarning: Matplotlib is currently using agg, which is a non-GUI backend, so cannot show the figure.
  plt.show()

Expected behavior This message above should not appear.

Additional context

• how I installed pip install impedance==0.3.0
• operating system windows 10

[abdullahsumbal]

Update fixed the issue. Thanks a lot. 👍

[mdmurbach]

This should be fixed in v0.3.1!

You can update with pip install --upgrade impedance. Please let me know if you still run into any issues 😄