code: def set_global_fontsize_from_fig(fig, scale=1.5):
      
  
      fig_size_inch = fig.get_size_inches()
      fig_size_len_geom_mean = (fig_size_inch[0] * fig_size_inch[1]) ** 0.5
      rcParams['font.size'] = fig_size_len_geom_mean * scale
      return rcParams['font.size']
docs: Set matplotlib.rcParams['font.size'] value so that
      all texts on a plot would look nice in terms of fontsize.
  
      [NOTE] The formula for the font size is:
  
      fontsize = sqrt(fig_area) * 'scale'
  
      where fig_area = fig_height * fig_width (in inch)