"""Return the magic string used to recognize byte-compiled code files."""

_PY_SOURCE_SUFFIX = ('.py', 'U', PY_SOURCE)

_PKG_DIRECTORY_SUFFIX = ('', '', PKG_DIRECTORY)

  """Return a list that describes the files that find_module() looks for."""

  return [_PY_SOURCE_SUFFIX]

def find_module(name, path=None):

  """Try to find the named module on the given search path or sys.path."""

  if path == None:

    path = sys.path

  for directory in path:

    filename = os.path.join(directory, '%s.py' % name)

    if os.path.exists(filename):

      return open(filename, 'U'), filename, _PY_SOURCE_SUFFIX

    dirname = os.path.join(directory, name)

    filename = os.path.join(dirname, '__init__.py')

    if os.path.exists(filename):

      return None, dirname, _PKG_DIRECTORY_SUFFIX

  raise ImportError('No module named %s' % name)

def load_module(name, file_, pathname, description):

  """Load or reload the specified module.

  Please note that this function has only rudimentary supported on App Engine:

  Only loading packages is supported.

  """

  suffix, mode, type_ = description

  if type_ == PKG_DIRECTORY:

    if name in sys.modules:

      mod = sys.modules[name]

    else:

      mod = new_module(name)

      sys.modules[name] = mod

    filename = os.path.join(pathname, '__init__.py')

    mod.__file__ = filename

    execfile(filename, mod.__dict__, mod.__dict__)

    return mod

  else:

    raise NotImplementedError('Only importing packages is supported on '

                              'App Engine')

  """Return a new empty module object."""

  return type(sys)(name)

def init_builtin(name):

  raise NotImplementedError('This function is not supported on App Engine.')

def init_frozen(name):

  raise NotImplementedError('This function is not supported on App Engine.')

def load_compiled(name, pathname, file_=None):

  raise NotImplementedError('This function is not supported on App Engine.')

def load_dynamic(name, pathname, file_=None):

  raise NotImplementedError('This function is not supported on App Engine.')

def load_source(name, pathname, file_=None):

  raise NotImplementedError('This function is not supported on App Engine.')

  """Null importer object"""