plot_pie_sum appends the builtin slice type instead of the computed slice size

src/graphing/plotting.py:110-113:
for idx, datapoints in enumerate(datapoint_groups):
pslice = sum(datapoints)
pie_slices_sizes.append(slice) # <-- appends builtin `slice`, not `pslice`
labels[idx] = labels[idx] + " : " + str(pslice)
pslice is computed and used in the label, but the list gets the builtin slice type
object. So plot.pie() receives a list of type objects rather than numbers.

Open src/graphing/plotting.py lines 110-113 and inspect plot_pie_sum, starting with the value appended to pie_slices_sizes. Run the plotting entry point that calls plot.pie() and verify it receives the computed numeric slice sizes while the labels still show those sums.

Written by the indexing model from the issue text.