\title{Retrieve sample contributions stored in an \code{\link{IcaSet}} object
   as a list.}
 \description{This generic function retrieves, from an IcaSet object,
   the sample contributions contained in
   the attribute \code{A} as
   a list where sample IDs are preserved.
   \item{object}{Object of class \code{IcaSet}.}
   \code{Alist} returns a list whose length equals the number of
   components contained in the \code{IcaSet} object. Each element of this
   list contains a vector of sample contributions 
   indexed by the sample IDs.
 \author{Anne Biton}