2.2.0-beta2版本以Append方式导出多个sheet时，当Append的ICollection均为空集合时，报 “Tablename is not unique”错误，比如：
new ExcelExporter().Append(new List<Student>()).Append(new List<Teacher>()).ExportAppendData("test.xlsx");
详细错误信息如下：
System.ArgumentException
HResult=0x80070057
Message=Tablename is not unique
Source=EPPlus
StackTrace:
at OfficeOpenXml.Table.ExcelTableCollection.Add(ExcelAddressBase Range, String Name)
at Magicodes.ExporterAndImporter.Excel.Utility.ExportHelper`1.AddHeader()
at Magicodes.ExporterAndImporter.Excel.Utility.ExportHelper`1.AddHeaderAndStyles()
at Magicodes.ExporterAndImporter.Excel.Utility.ExportHelper`1.Export(ICollection`1 dataItems)
at Magicodes.ExporterAndImporter.Excel.ExcelExporter.Append[T](ICollection`1 dataItems)
at Magicodes.IE.Excel.Program.Export() in E:\Technology\Magicodes.IE.Excel\Magicodes.IE.Excel\Program.cs:line 29
at Magicodes.IE.Excel.Program.Main(String[] args) in E:\Technology\Magicodes.IE.Excel\Magicodes.IE.Excel\Program.cs:line 15
@xin-lai 请帮忙尽快解决，谢谢
2.2.0-beta2版本以Append方式导出多个sheet时，当Append的ICollection均为空集合时，报 “Tablename is not unique”错误，比如：
new ExcelExporter().Append(new List<Student>()).Append(new List<Teacher>()).ExportAppendData("test.xlsx");详细错误信息如下：
@xin-lai 请帮忙尽快解决，谢谢