parameters: (filename, warn_on_readonly=True)
return_statement: return multistore
docstring: A helper method to initialize the multistore with proper locking.
  
    Args:
      filename: The JSON file storing a set of credentials
      warn_on_readonly: if True, log a warning if the store is readonly
  
    Returns:
      A multistore object
docstring_summary: A helper method to initialize the multistore with proper locking.
docstring_tokens: A helper method to initialize the multistore with proper locking .
function: def _get_multistore(filename, warn_on_readonly=True):
    """A helper method to initialize the multistore with proper locking.
  
    Args:
      filename: The JSON file storing a set of credentials
      warn_on_readonly: if True, log a warning if the store is readonly
  
    Returns:
      A multistore object
    """
    filename = os.path.expanduser(filename)
    _multistores_lock.acquire()
    try:
      multistore = _multistores.setdefault(
          filename, _MultiStore(filename, warn_on_readonly=warn_on_readonly))
    finally:
      _multistores_lock.release()
    return multistore
function_tokens: def _get_multistore ( filename , warn_on_readonly = True ) : filename = os . path . expanduser ( filename ) _multistores_lock . acquire ( ) try : multistore = _multistores . setdefault ( filename , _MultiStore ( filename , warn_on_readonly = warn_on_readonly ) ) finally : _multistores_lock . release ( ) return multistore