def mark_new_entries(response)
      digests = summary_digests

      # For each entry in the responses object, mark @_seen as false if the 
      # digest of this entry doesn't exist in the cached object.
      response.entries.each do |e|
        seen = digests.include?(digest_for(e))
        e.instance_variable_set(:@_seen, seen)
      end
      
      response
    end
def mark_new_entries(response)
      digests = summary_digests

      # For each entry in the responses object, mark @_seen as false if the 
      # digest of this entry doesn't exist in the cached object.
      response.entries.each do |e|
        seen = digests.include?(digest_for(e))
        e.instance_variable_set(:@_seen, seen)
      end
      
      response
    end
Marks entries as either seen or not seen based on the unique signature of
 the entry, which is calculated by taking the MD5 of common attributes.