title: Flier colors in boxplot with matplotlib
body: <p>According to the <a href="https://matplotlib.org/api/_as_gen/matplotlib.axes.Axes.boxplot.html#matplotlib.axes.Axes.boxplot" rel="noreferrer">documentation</a>, the <code>Axes.boxplot</code> function takes a dictionary <code>flierprop</code> as argument to define the properties of the outliers. Unfortunately, I can't find the documentation concerning this dictionary. In particular, I would like to define the color of the border of the marker.</p>
  
  <p>By default, empty circles are drawn. One can set the face color, <a href="https://matplotlib.org/examples/statistics/boxplot_demo.html" rel="noreferrer">as shown in the example</a>. Nevertheless, the circle border is always a black line. I tried with the keys <code>color</code> and <code>markercolor</code> (the former has no effect, the latter produces an error).</p>
  
  <p><strong>What should I do to set a color for the marker line?</strong></p>