Matplotlib doesn't forget previous data when saving figures with savefig
<pre><code>import matplotlib.pyplot as plt
plt.plot([1,2,3],[1,2,3],'ro')
plt.axis([-4,4,-4,4])
plt.savefig('azul.png')
plt.plot([0,1,2],[0,0,0],'ro')
plt.axis([-4,4,-4,4])
plt.savefig('amarillo.png')
</code></pre>

<p>Output:</p>

<p><a href="https://i.stack.imgur.com/ebDFM.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/ebDFM.png" alt="azul"></a>
<a href="https://i.stack.imgur.com/5k78i.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/5k78i.png" alt="amarillo"></a></p>

<p>Why does this happen and how to solve?</p>