class CrosstabReport(ReportView):
    report_title = _("Cross tab Report")
    report_description = _("A basic crosstab: clients as rows, products as columns. "
                           "Each cell holds the sales value for that client–product combination, "
                           "with a total column on the right.")
    report_model = SalesTransaction
    group_by = "client"
    # date_field = "date"

    columns = [
        "name",
        # You can customize where the crosstab columns are displayed in relation to the other columns
        "__crosstab__",

        # This is the same as the calculation in the crosstab,
        # but this one will be on the whole set. IE total value.
        ComputationField.create(Sum, "value", verbose_name=_("Total Value")),
    ]

    crosstab_field = "product"
    crosstab_columns = [
        ComputationField.create(Sum, "value", verbose_name=_("Value")),
    ]