title: Matplotlib: how to adjust zorder of second legend?
body: <p>Here is an example that reproduces my problem:</p>
  
  <pre><code>import matplotlib.pyplot as plt
  import numpy as np
  
  data1,data2,data3,data4 = np.random.random(100),np.random.random(100),np.random.random(100),np.random.random(100)
  
  fig,ax = plt.subplots()
  
  ax.plot(data1)
  ax.plot(data2)
  ax.plot(data3)
  
  ax2 = ax.twinx()
  ax2.plot(data4)
  
  plt.grid('on')
  ax.legend(['1','2','3'], loc='center')
  ax2.legend(['4'], loc=1)
  </code></pre>
  
  <p><img src="https://i.stack.imgur.com/4pGP2.png" alt="enter image description here"></p>
  
  <p>How can I get the legend in the center to plot on top of the lines?</p>