Set the file path that needs to be locked.

        :Parameters:
            #. filePath (None, path): The file that needs to be locked. When given and a lock
               is acquired, the file will be automatically opened for writing or reading
               depending on the given mode. If None is given, the locker can always be used
               for its general purpose as shown in the examples.

def set_file_path(self, filePath):
        """
        Set the file path that needs to be locked.

        :Parameters:
            #. filePath (None, path): The file that needs to be locked. When given and a lock
               is acquired, the file will be automatically opened for writing or reading
               depending on the given mode. If None is given, the locker can always be used
               for its general purpose as shown in the examples.
        """
        if filePath is not None:
            assert isinstance(filePath, basestring), "filePath must be None or string"
            filePath = str(filePath)
        self.__filePath = filePath