'Header for the Excel sheet
@param sheet: the sheet
@param data: the data dict from extract()
@return: the number of rows in the header'

def summary(self, sheet, data=None):

    length = 3
    if ((sheet is not None) and (data is not None)):
        T = current.T
        output = (('Date', S3DateTime.date_represent(self.date, utc=True)), ('Previous    Total', data['old_total']), ('Admissions', data['ins']), ('Departures', data['outs']), ('Current    Total', data['new_total']))
        import xlwt
        label_style = xlwt.XFStyle()
        label_style.font.bold = True
        col_index = 3
        for (label, value) in output:
            label_ = s3_unicode(T(label))
            value_ = s3_unicode(value)
            width = max(len(label_), len(value_))
            sheet.col(col_index).width = max((width * 310), 2000)
            current_row = sheet.row(0)
            current_row.write(col_index, label_, label_style)
            current_row = sheet.row(1)
            current_row.write(col_index, value_)
            col_index += 1
    return length
