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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 register_backends(vars):
 """Register backends for use with models. `vars` should be a dictionary of variables obtained from e.g. `locals()`, at least some of which are Backend classes, e.g. from imports. """

    new_backends = {x.replace('Backend', ''): cls
                    for x, cls in vars.items()
                    if inspect.isclass(cls) and issubclass(cls, Backend)}
    available_backends.update(new_backends)