code: public void write( SystemInputDef systemInput)
      {
      xmlWriter_.writeDeclaration();
  
      xmlWriter_
        .element( SYSTEM_TAG)
        .attribute( NAME_ATR, systemInput.getName())
        .content( () ->
          {
          writeAnnotations( systemInput);
          toStream( systemInput.getFunctionInputDefs()).forEach( this::writeFunction);
          })
        .write();
      }
docs: Writes the given system test definition the form of an XML document.