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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def _chunk_setitem(self, chunk_coords, chunk_selection, value, fields=None):
 """Replace part or whole of a chunk. Parameters chunk_coords : tuple of ints Indices of the chunk. chunk_selection : tuple of slices Location of region within the chunk. value : scalar or ndarray Value to set. """


        if self._synchronizer is None:
            # no synchronization
            lock = nolock
        else:
            # synchronize on the chunk
            ckey = self._chunk_key(chunk_coords)
            lock = self._synchronizer[ckey]

        with lock:
            self._chunk_setitem_nosync(chunk_coords, chunk_selection, value,
                                       fields=fields)