title: Two line styles in legend
body: <p>I have a plot with two line styles (solid and dashed). I would like them to be used for the same legend entry. The code below produces the typical legend, with two entries.</p>
  
  <pre><code>import matplotlib.pyplot as plt
  import numpy as np
  
  xy = np.linspace(0,10,10)
  
  plt.figure()
  plt.plot(xy,xy, c='k', label='solid')
  plt.plot(xy,xy+1, c='k', ls='dashed', label='dashed')
  plt.plot(xy,xy-1, c='k', ls='dashed')
  plt.legend()
  
  plt.show()
  </code></pre>
  
  <p>What I would like is something similar to this:</p>
  
  <p><img src="https://i.stack.imgur.com/fLwf6.png" alt=""></p>
  
  <p>I have tried playing with proxy artists, but can't seem to get two lines, offset from each other to appear for one entry.</p>