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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 tensor_space_impl(impl):
 """Tensor space class corresponding to the given impl name. Parameters impl : str Name of the implementation, see `tensor_space_impl_names` for the full list. Returns ------- tensor_space_impl : type Class inheriting from `TensorSpace`. Raises ------ ValueError If ``impl`` is not a valid name of a tensor space imlementation. """

    if impl != 'numpy':
        # Shortcut to improve "import odl" times since most users do not use
        # non-numpy backends
        _initialize_if_needed()

    try:
        return TENSOR_SPACE_IMPLS[impl]
    except KeyError:
        raise ValueError("`impl` {!r} does not correspond to a valid tensor "
                         "space implmentation".format(impl))