python – django xlsxwriter中的DateTime问题

def export_myreport(request,sd,ed):
    from xlsxwriter.workbook import Workbook
    import cStringIO as StringIO
    from django.utils.encoding import smart_str

    # create a workbook in memory
    output = StringIO.StringIO()

    wb = Workbook(output)

    bg = wb.add_format({'bg_color': '#9CB640','font_color': 'black'})
    bg2 = wb.add_format({'bg_color': '#FFFFFF','font_color': 'black'})

    ws = wb.add_worksheet('My Report')

    row_num = 0

    summary = MyModel.objects.filter(time__range = (sd,ed)).select_related()

    row_num += 2
    row = [
        smart_str(u"Time"),smart_str(u"Item"),smart_str(u"User")
    ]
    for col_num in xrange(len(row)):
        ws.write(row_num,col_num,row[col_num],bg)

    for s in summary:
        row_num += 1
        row2 = [
            s.time,s.model_name,s.user.first_name
        ]
        for col_num in xrange(len(row2)):
            ws.write(row_num,row2[col_num],bg2)

    wb.close()

    output.seek(0)
    response = HttpResponse(output.read(),content_type="application/vnd.openxmlformats-officedocument.spreadsheetml.sheet")
    response['Content-Disposition'] = "attachment; filename=myreport.xlsx"

    return response

但我在使用DateTime格式时遇到了一些问题！也许我在这里缺少什么？

这是我得到的错误：

TypeError at /myapp/export_myreport/2015-05-01/2015-05-19
can't subtract offset-naive and offset-aware datetimes

编辑：

这就是我在我的html中调用url的方式：

<a href="export_myreport/{{begindate}}/{{enddate}}" class="btn btn-default pull-right" role="button">Export to XLSX</a>

这里{{begindate}}和{{enddate}}是角度变量.