code: def copy_to_scratch(file_mapping, dry_run=True):
          
          for key, value in file_mapping.items():
              if not os.path.exists(key):
                  continue
              if dry_run:
                  print ("copy %s %s" % (key, value))
              else:
                  print ("copy %s %s" % (key, value))
                  copyfile(key, value)
  
          return file_mapping
docs: Copy input files to scratch area