module ActiveFedora::SemanticNode::ClassMethods

def relationships_to_rels_ext(pid, relationships=self.relationships)

Note: This method is implemented on SemanticNode instead of RelsExtDatastream because SemanticNode contains the relationships array
@pid
Creates a RELS-EXT datastream for insertion into a Fedora Object 
def relationships_to_rels_ext(pid, relationships=self.relationships)
  starter_xml = <<-EOL
  <rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#">
    <rdf:Description rdf:about="info:fedora/#{pid}">
    </rdf:Description>
  </rdf:RDF>
  EOL
  xml = REXML::Document.new(starter_xml)

  # Iterate through the hash of predicates, adding an element to the RELS-EXT for each "object" in the predicate's corresponding array.
  self.outbound_relationships.each do |predicate, targets_array|
    targets_array.each do |target|
      #puts ". #{predicate} #{target}"
      xml.root.elements["rdf:Description"].add_element(predicate_lookup(predicate), {"xmlns" => "info:fedora/fedora-system:def/relations-external#", "rdf:resource"=>target})
    end
  end
  xml.to_s
end