title: jupyter notebook shows error message for matplotlib Bad key "text.kerning_factor"
body: <pre><code>import pandas as pd 
  import numpy as np
  import matplotlib.pyplot as plt
  </code></pre>
  
  <p>Bad key "text.kerning_factor" on line 4 in
  /home/samyak/anaconda3/lib/python3.7/site-packages/matplotlib/mpl-data/stylelib/_classic_test_patch.mplstyle.
  You probably need to get an updated matplotlibrc file from
  <a href="https://github.com/matplotlib/matplotlib/blob/v3.1.3/matplotlibrc.template" rel="noreferrer">https://github.com/matplotlib/matplotlib/blob/v3.1.3/matplotlibrc.template</a>
  or from the matplotlib source distribution</p>