def save(self, obj):
        """ Subclass the save method, to hash ndarray subclass, rather
            than pickling them. Off course, this is a total abuse of
            the Pickler class.
        """
        if isinstance(obj, self.np.ndarray) and not obj.dtype.hasobject:
            # Compute a hash of the object
            # The update function of the hash requires a c_contiguous buffer.
            if obj.shape == ():
                # 0d arrays need to be flattened because viewing them as bytes
                # raises a ValueError exception.
                obj_c_contiguous = obj.flatten()
            elif obj.flags.c_contiguous:
                obj_c_contiguous = obj
            elif obj.flags.f_contiguous:
                obj_c_contiguous = obj.T
            else:
                # Cater for non-single-segment arrays: this creates a
                # copy, and thus aleviates this issue.
                # XXX: There might be a more efficient way of doing this
                obj_c_contiguous = obj.flatten()

            # memoryview is not supported for some dtypes, e.g. datetime64, see
            # https://github.com/numpy/numpy/issues/4983. The
            # workaround is to view the array as bytes before
            # taking the memoryview.
            self._hash.update(
                self._getbuffer(obj_c_contiguous.view(self.np.uint8)))

            # We store the class, to be able to distinguish between
            # Objects with the same binary content, but different
            # classes.
            if self.coerce_mmap and isinstance(obj, self.np.memmap):
                # We don't make the difference between memmap and
                # normal ndarrays, to be able to reload previously
                # computed results with memmap.
                klass = self.np.ndarray
            else:
                klass = obj.__class__
            # We also return the dtype and the shape, to distinguish
            # different views on the same data with different dtypes.

            # The object will be pickled by the pickler hashed at the end.
            obj = (klass, ('HASHED', obj.dtype, obj.shape, obj.strides))
        elif isinstance(obj, self.np.dtype):
            # Atomic dtype objects are interned by their default constructor:
            # np.dtype('f8') is np.dtype('f8')
            # This interning is not maintained by a
            # pickle.loads + pickle.dumps cycle, because __reduce__
            # uses copy=True in the dtype constructor. This
            # non-deterministic behavior causes the internal memoizer
            # of the hasher to generate different hash values
            # depending on the history of the dtype object.
            # To prevent the hash from being sensitive to this, we use
            # .descr which is a full (and never interned) description of
            # the array dtype according to the numpy doc.
            klass = obj.__class__
            obj = (klass, ('HASHED', obj.descr))
        Hasher.save(self, obj)
Subclass the save method, to hash ndarray subclass, rather
            than pickling them. Off course, this is a total abuse of
            the Pickler class.