def new_app_text(db):
    """
    Returns /docProps/app.xml text

    :param pylightxl.Database db: database contains sheetnames, and their data
    :return str: /docProps/app.xml text
    """
    xml_base = (
        '<?xml version="1.0" encoding="UTF-8" standalone="yes"?>\r\n<Properties xmlns:vt="http://schemas.openxmlformats.org/officeDocument/2006/docPropsVTypes" xmlns="http://schemas.openxmlformats.org/officeDocument/2006/extended-properties">\r\n<Application>Microsoft Excel</Application>\r\n<DocSecurity>0</DocSecurity>\r\n<ScaleCrop>false</ScaleCrop>\r\n<HeadingPairs>\r\n<vt:vector baseType="variant" size="2">\r\n<vt:variant>\r\n<vt:lpstr>Worksheets</vt:lpstr>\r\n</vt:variant>\r\n<vt:variant>\r\n<vt:i4>{num_sheets}</vt:i4>\r\n</vt:variant>\r\n</vt:vector>\r\n</HeadingPairs>\r\n<TitlesOfParts>\r\n<vt:vector baseType="lpstr" size="{num_sheets}">\r\n{many_tag_vt}\r\n</vt:vector>\r\n</TitlesOfParts>\r\n<Company></Company>\r\n<LinksUpToDate>false</LinksUpToDate>\r\n<SharedDoc>false</SharedDoc>\r\n<HyperlinksChanged>false</HyperlinksChanged>\r\n<AppVersion>16.0300</AppVersion>\r\n</Properties>'
        )
    tag_vt = '<vt:lpstr>{sheet_name}</vt:lpstr>\r\n'
    num_sheets = len(db.ws_names)
    many_tag_vt = ''
    for sheet_name in db.ws_names:
        many_tag_vt += tag_vt.format(sheet_name=sheet_name)
    rv = xml_base.format(num_sheets=num_sheets, many_tag_vt=many_tag_vt)
    return rv
