How do I set label for an already plotted line in matplotlib?
<p>In my code I've already executed</p>

<pre><code>ax.plot(x, y, 'b.-', ...)
</code></pre>

<p>and need to be able to set the label for the corresponding line after the fact, to have the same effect as if I'd</p>

<pre><code>ax.plot(x, y, 'b.-', label='lbl', ...)
</code></pre>

<p>Is there a way to do this in Matplotlib?</p>