code: def get_oauth2_metadata_from_conformance(strict=true)
        options = {
          authorize_url: nil,
          token_url: nil
        }
        begin
          capability_statement.rest.each do |rest|
            if strict
              rest.security.service.each do |service|
                service.coding.each do |coding|
                  next unless coding.code == 'SMART-on-FHIR'
                   options.merge! get_oauth2_metadata_from_service_definition(rest)
                end
              end
            else
              options.merge! get_oauth2_metadata_from_service_definition(rest)
            end
          end
        rescue => e
          FHIR.logger.error "Failed to locate SMART-on-FHIR OAuth2 Security Extensions: #{e.message}"
        end
        options.delete_if { |_k, v| v.nil? }
        options.clear if options.keys.size != 2
        options
      end
docs: Get the OAuth2 server and endpoints from the capability statement
   (the server should not require OAuth2 or other special security to access
   the capability statement).
   <rest>
     <mode value="server"/>
     <documentation value="All the functionality defined in FHIR"/>
     <security>
     <extension url="http://fhir-registry.smarthealthit.org/StructureDefinition/oauth-uris">
       <extension url="register">
         <valueUri value="https://authorize-dstu2.smarthealthit.org/register"/>
       </extension>
       <extension url="authorize">
         <valueUri value="https://authorize-dstu2.smarthealthit.org/authorize"/>
       </extension>
       <extension url="token">
         <valueUri value="https://authorize-dstu2.smarthealthit.org/token"/>
       </extension>
     </extension>
     <service>
       <coding>
         <system value="http://hl7.org/fhir/vs/restful-security-service"/>
         <code value="OAuth2"/>
       </coding>
       <text value="OAuth version 2 (see oauth.net)."/>
     </service>
     <description value="SMART on FHIR uses OAuth2 for authorization"/>
   </security>