hey guys, i am very new to Soap and Zimbra. here are my questions:

1. I was reading the API and I was trying to create and get distribution list

<a n="...">...</a>+

<GetDistributionListRequest [limit="{limit}"] [offset="{offset}"]
<dl by="id|name">...</dl>

so my question is that what are these tags 'a', 'n' and 'dl' mean, and what should go inside of 'a' and 'dl' tag.(those ... thingy )

2. s = SOAP::RPC:river.new('https://mail.twistage.com:7071/service/admin/soap/','urn:zimbraAdmin')

this will generate
<dl xsi:type="xsd:string">test</dl>

so my question is that how do i add attribute inside dl like 'by'
<dl by=''></dl>

Please help. Thanks in advance.