title: In Matplotlib, how can I clear an axes' contents without erasing its axis labels?
body: <p>Is there an alternative to axes.clear() that leaves the axis labels untouched, while erasing the axes' contents?</p>
  
  <p>Context: 
  I have an interactive script that flips through some flow images, and for each image, plots it using axes.quiver(). If I don't call axes.clear() between calls to axes.quiver(), each quiver() call just adds more arrows to the plot without first erasing the previously added arrows. However, when I call axes.clear(), it nukes the axes labels. I can re-set them, but it's a bit annoying.</p>