More verbose error message for plotting

nifty5/plotting/plot.py

@@ -359,7 +359,7 @@ def plot_finish(**kwargs):
     ny = kwargs.pop("ny", int(np.ceil(np.sqrt(nplot))))
     if nx*ny < nplot:
         raise ValueError(
-            'Figure dimensions not sufficient for number of plots')
+            'Figure dimensions not sufficient for number of plots. Available plot slots: {}, number of plots: {}'.format(nx*ny, nplot))
     xsize = kwargs.pop("xsize", 6)
     ysize = kwargs.pop("ysize", 6)
     fig.set_size_inches(xsize, ysize)