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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 close(key):
 """Closes and unregister the context figure corresponding to the key. Parameters key: hashable Any variable that can be used as a key for a dictionary """

    figure_registry = _context['figure_registry']
    if key not in figure_registry:
        return
    if _context['figure'] == figure_registry[key]:
        figure()
    fig = figure_registry[key]
    if hasattr(fig, 'pyplot'):
        fig.pyplot.close()
    fig.close()
    del figure_registry[key]
    del _context['scale_registry'][key]