title: Matplotlib remove patches from figure
body: <p>In my case, I want to remove one of the circle when clicking reset button. However, ax.clear() would clear all circles on the current figure. </p>
  
  <p>Can someone tell me how to remove only part of the patches?</p>
  
  <pre><code>import matplotlib.patches as patches
  import matplotlib.pyplot as plt
  from matplotlib.widgets import Button
  
  fig = plt.figure()
  ax = fig.add_subplot(111) 
  
  circle1 = patches.Circle((0.3, 0.3), 0.03, fc='r', alpha=0.5)
  circle2 = patches.Circle((0.4, 0.3), 0.03, fc='r', alpha=0.5)
  button = Button(plt.axes([0.8, 0.025, 0.1, 0.04]), 'Reset', color='g', hovercolor='0.975')
  ax.add_patch(circle1)
  ax.add_patch(circle2)
  
  def reset(event):
      '''what to do here'''
      ax.clear()
  
  button.on_clicked(reset)
  plt.show()
  </code></pre>