title: matplotlib set all plots linewidth in a figure at once
body: <pre><code>import matplotlib.pyplot as plt
  import numpy as np
  fig = plt.figure()
  ax = fig.add_subplot(111)
  ax.plot(range(10))
  ax.plot(2 * range(10))
  </code></pre>
  
  <p>I have a function (basic_axis(ax)) that will set spines linewidth (ax.spines.set_linewidth()), tick length (ax.tick_paras(...), ... but I don't find how to also set all plots linewidth with one value. Is it possible to do it through a function that takes only ax as parameter?</p>