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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 concatenate(self, tpl, axis=None):
 """ Concatenates sparse tensors. Parameters tpl : tuple of sparse tensors Tensors to be concatenated. axis : int, optional Axis along which concatenation should take place """

        if axis is None:
            raise NotImplementedError(
                'Sparse tensor concatenation without axis argument is not supported'
            )
        T = self
        for i in range(1, len(tpl)):
            T = _single_concatenate(T, tpl[i], axis=axis)
        return T