def add_properties(hash)
      hash.each do |identity, property|
        @properties[flexible identity] ||= property.class.new
        @properties[flexible identity].concat property
      end
      update_human_readable_methods
    end
def add_properties(hash)
      hash.each do |identity, property|
        @properties[flexible identity] ||= property.class.new
        @properties[flexible identity].concat property
      end
      update_human_readable_methods
    end
Takes a hash {identity => property} and adds those to the current node.
 If a property already exists, it will append to it.