'Retrieve a file listing into the given protocol instance.
This method issues the \'LIST\' FTP command.
@param path: path to get a file listing for.
@param protocol: a L{Protocol} instance, probably a
L{FTPFileListProtocol} instance.  It can cope with most common file
listing formats.
@return: L{Deferred}'

def list(self, path, protocol):

    if (path is None):
        path = ''
    return self.receiveFromConnection([('LIST    ' + self.escapePath(path))], protocol)
