title: Python Tkinter Canvas Draw Semicircle
body: <p>It'd seem so obvious at first that I never thought of how I would do this - how can I draw a semicircle?
  I've tried using an chord:</p>
  
  <pre><code>canvas.create_arc(x1, y1, x2, y2, style="chord",...)
  </code></pre>
  
  <p>But no combination of coordinates I can think of work. So I tried using an arc:</p>
  
  <pre><code>canvas.create_arc(x1, y1, x2, y2, style="arc",...)
  </code></pre>
  
  <p>Which also doesn't work - and pieslice doesn't either.</p>
  
  <p>In summary, how can I make a semicircle using  tkinter? (as in like canvas.create...)</p>