code: def write_dockerfile(self, output_dir):
          
          if not os.path.exists(output_dir):
              os.makedirs(output_dir)
  
          lines = []
          for istep, step in enumerate(self.steps):
              if istep == 0:
                  lines.extend(step.dockerfile_lines)
              else:
                  lines.extend(step.dockerfile_lines[1:])
          path = os.path.join(output_dir, 'Dockerfile.%s' % self.imagename)
          with open(path, 'w') as outfile:
              outfile.write('\n'.join(lines))
          print('Wrote %s' % path)
docs: Used only to write a Dockerfile that will NOT be built by docker-make