code: def define_natives(cls):
          
          if len(cls._natives) > 0:
              return
  
          glob_pattern = os.path.join(os.path.dirname(__file__), "native", "*.py")
          for filename in glob.glob(glob_pattern):
              basename = os.path.basename(filename).replace(".py", "")
              if basename == "__init__":
                  continue
  
              try:
                  mod_base = __import__("pfp.native", globals(), locals(), fromlist=[basename])
              except Exception as e:
                  sys.stderr.write("cannot import native module {} at '{}'".format(basename, filename))
                  raise e
                  continue
  
              mod = getattr(mod_base, basename)
              setattr(mod, "PYVAL", fields.get_value)
              setattr(mod, "PYSTR", fields.get_str)
docs: Define the native functions for PFP