Pygal : I try to change the style parameters of a chart but nothing change

Hello,

I'm using Python 3.11.7 and pygal 3.0.5.
I have in my code a small function to plot a specific chart (see below). This function returns a svg version of the chart that is then inserted in a HTML document. Globally this function works very well but...
My problem : **when I change the values of most of the style parameters, nothing change in the rendered chart**. For instance the font size doesn't change, the margin doesn't change. There is only one parameter that, when modified, change the aspect of the chart : spacing.

Thank you very much for your precious help, since I didn't find nothing related to that on the web. I'm lost

The code
```
def FigWalkCycleTimes(Td,fig_title,szx,szy):

# Get data
s_sup_time_L = round(float(Td[0]["S_Supp_Time_L"]),2)
s_sup_time_R = round(float(Td[0]["S_Supp_Time_R"]),2)
d_sup_time_L = round(float(Td[0]["D_Supp_TimeL"])/2,2)
d_sup_time_R = round(float(Td[0]["D_Supp_TimeR"])/2,2)
swing_time_L = round(float(Td[0]["Swing_Time_L"]),2)
swing_time_R = round(float(Td[0]["Swing_Time_L"]),2)

bar_chart = pygal.HorizontalStackedBar(width=szx,height=szy,explicit_size=True,
legend_at_bottom=True,spacing=10,margin_top=10,margin_bottom=10,value_font_size=5,
label_font_size=10,legend_font_size = 12,legend_font_family='Courrier',
human_readable=True,
print_values=True,pretty_print=True)
bar_chart.title = fig_title
bar_chart.x_labels = 'Left', 'Right'
bar_chart.add('First double support (s)', [d_sup_time_L, d_sup_time_R])
bar_chart.add('Single support (s)', [s_sup_time_L, s_sup_time_R])
bar_chart.add('Second double support (s)',[d_sup_time_L, d_sup_time_R])
bar_chart.add('Swing duration (s)',[swing_time_L, swing_time_R])
svg = bar_chart.render_data_uri()
return(svg)
```

Start by reproducing the FigWalkCycleTimes function with Python 3.11.7 and pygal 3.0.5, then inspect the SVG returned by render_data_uri() to compare changes to value_font_size, label_font_size, legend_font_size, and margins. Done means determining why those style parameters do not affect the rendered chart and either correcting the behavior or documenting the supported parameters.

Written by the indexing model from the issue text.