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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 mesh_axis_to_tensor_axis(self, mesh_ndims):
 """For each mesh axis, which Tensor axis maps to it. Args: mesh_ndims: int. Returns: Tuple of optional integers, with length mesh_ndims. """

    ta2ma = self._tensor_axis_to_mesh_axis
    return tuple(
        [ta2ma.index(mesh_axis) if mesh_axis in ta2ma else None
         for mesh_axis in xrange(mesh_ndims)])