Resolve "release v1.4.0"

Closes #317 (closed)

mlair/plotting/data_insight_plotting.py

@@ -691,7 +691,7 @@ class PlotPeriodogram(AbstractPlotClass):  # pragma: no cover
                     upper, lower = ma.max().mean(axis=1).values.flatten(), ma.min().mean(axis=1).values.flatten()
                     ax.fill_between(self.f_index, lower, upper, color="light" + c, alpha=0.5, label=None)
             self._format_figure(ax, var)
-            ax.legend()
+            ax.legend(loc="upper center", ncol=max_iter)
             pdf_pages.savefig()
         # close all open figures / plots
         pdf_pages.close()