Handling selections XML documents.
Load a selections document.
Create a selections value from a file (parse + create).
The role of the root selection.
The command on root_role to run.
The selection for root_role.
Iterate over the <selection> elements.
Check whether the XML of two sets of selections are the same, ignoring whitespace.
Like get_selected, but raise an exception if not found.
Convert a selections document to XML in the latest format.
Look up this selection's directory.
Get the URL of the feed this selection came from.
Get the globally unique ID of this selection (feed + ID)