title: How to draw a line with matplotlib?
body: <p>I cannot find a way to draw an arbitrary line with <code>matplotlib</code> Python library.  It allows to draw horizontal and vertical lines (with <code>matplotlib.pyplot.axhline</code> and <code>matplotlib.pyplot.axvline</code>, for example), but i do not see how to draw a line through two given points <code>(x1, y1)</code> and <code>(x2, y2)</code>. Is there a way? Is there a simple way?</p>