def createChunk(self, cx, cz):
        '''
        Creates a chunk at the specified chunk coordinates if it doesn't exist already
        
        :param cx: The X coordinate of the chunk
        :type cx: int
        :param cz: The Z coordinate of the chunk
        :type cz: int
        :raises ValueError: Raise when a chunk is already present/generated at the specified X and Z coordinates
        '''
        if self.containsChunk(cx, cz):
            raise ValueError("{0}:Chunk {1} already present!".format(self, (cx, cz)))
        if self._allChunks is not None:
            self._allChunks.add((cx, cz))

        self._storeLoadedChunkData(AnvilChunkData(self, (cx, cz), create=True))
        self._bounds = None

        Creates a chunk at the specified chunk coordinates if it doesn't exist already
        
        :param cx: The X coordinate of the chunk
        :type cx: int
        :param cz: The Z coordinate of the chunk
        :type cz: int
        :raises ValueError: Raise when a chunk is already present/generated at the specified X and Z coordinates
        
pymclevel/infiniteworld.py