title: Python's matplotlib legend in separate axis with gridspec
body: <p>Let suppose I have a matplotlib's gridspec instance in a python script. What I want to do is to create two axis and have the plot in one axis and the legend in the other one. Something like</p>
  
  <pre><code>import numpy as np
  from matplotlib import gridspec, pyplot as plt
  
  x = np.linspace(0,100)
  y = np.sin(x)
  
  gs = gridspec.GridSpec( 100, 100 )
  ax1 = fig.add_subplot(gs[ :50, : ])
  ax2 = fig.add_subplot(gs[ 55:, : ])
  ax1.plot( s, y, label=r'sine' )
  ax2.legend() # ?? Here I want legend of ax1
  plt.show()
  </code></pre>
  
  <p>Is there any way of doing that?</p>