It is printing a Chart.
The trick is not to use display_text but value, as per below.
That will remove the single quote from numerical value.
HOWEVER, this example is only working for ONE SINGLE INVOCE ITEM ! Because the Data Range for a Chart is not constant, but growing, as there can be many items on the invoice.
The code is added for Reports/invoice.py
subtotal1 = invoices.subtotal.value
tax1 = invoices.tax.value
total1 = invoices.total.value
report.print_band('chart', locals())
The code is adding same values for the small legend above the Chart. It is not needed, but makes it easier to test. And this is the problem, since Legend is moving as Items are added.
But for STATIC pages, with known Data Range, it should be possible to print exactly the same report every time, all the times.
Cheers
D.