def size_for_work(work_id)
        argz = { fl: "id, #{file_size_field}",
                 fq: "{!join from=#{member_ids_field} to=id}id:#{work_id}" }
        files = ::FileSet.search_with_conditions({}, argz)
        files.reduce(0) { |sum, f| sum + f[file_size_field].to_i }
      end
def size_for_work(work_id)
        argz = { fl: "id, #{file_size_field}",
                 fq: "{!join from=#{member_ids_field} to=id}id:#{work_id}" }
        files = ::FileSet.search_with_conditions({}, argz)
        files.reduce(0) { |sum, f| sum + f[file_size_field].to_i }
      end
Calculate the size of all the files in the work
 @param work_id [String] identifer for a work
 @return [Integer] the size in bytes