title: Increment matplotlib string font size
body: <p>I am looking to increment the plot title font size, by bumping it from e.g. <code>medium</code> to <code>large</code>.</p>
  
  <p>My plots are getting their base font size as well as modifiers from a matplotlibrc <code>.conf</code> file.
  This is commonly expressed like so:</p>
  
  <pre><code>font.size : 8
  axes.titlesize : medium
  </code></pre>
  
  <p>Now, for one of my plots, I would like to increment the title font size, specifically.
  Were this a number (as it is for e.g. the linewidth), I could do something like:</p>
  
  <pre><code>from matplotlib import rcParams
  newsize = rcParams['lines.linewidth']*2
  </code></pre>
  
  <p>But this won't work as easily as that.
  I could, of course, use a dictionary or a series of <code>elif</code> statements - but I am thinking matplotlib, knowing how to interpret these strings, perhaps also has some function to increment them. Do you know of such a thing?</p>
  
  <p><strong>EDIT:</strong> Someone has suggested this would be a duplicate of some other question. This question specifically inquires about incrementing the "string font size" (as I have written in the title of the question). This means that setting the font size manually to some integer is not an option (unless there is a way to convert matplotlibrc's <code>small</code> or <code>medium</code> to integers - which would also be unique to this question).</p>