code: private IChemFile readChemFile(IChemFile chemFile) throws CDKException {
          IChemSequence chemSequence = chemFile.getBuilder().newInstance(IChemSequence.class);
  
          IChemModel chemModel = chemFile.getBuilder().newInstance(IChemModel.class);
          chemSequence.addChemModel(readChemModel(chemModel));
          chemFile.addChemSequence(chemSequence);
          return chemFile;
      }
docs: Read a ChemFile from a file in MDL RDF format.
  
  @param  chemFile The IChemFile
  @return          The IChemFile that was read from the RDF file.