data [,options] -> marshalled data
Convert an argument tuple or a Fault instance to an XML-RPC
request (or response, if the methodresponse option is used).
In addition to the data object, the following options can be given
as keyword arguments:
methodname: the method name for a methodCall packet
methodresponse: true to create a methodResponse packet.
If this option is used with a tuple, the tuple must be
a singleton (i.e. it can contain only one element).
encoding: the packet encoding (default is UTF-8)
All byte strings in the data structure are assumed to use the
packet encoding. Unicode strings are automatically converted,
where necessary.