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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 selection_strategy(oasis_obj, strategy='spectral-oasis', nsel=1, neig=None):
 """ Factory for selection strategy object Returns ------- selstr : SelectionStrategy Selection strategy object """

    strategy = strategy.lower()
    if strategy == 'random':
        return SelectionStrategyRandom(oasis_obj, strategy, nsel=nsel, neig=neig)
    elif strategy == 'oasis':
        return SelectionStrategyOasis(oasis_obj, strategy, nsel=nsel, neig=neig)
    elif strategy == 'spectral-oasis':
        return SelectionStrategySpectralOasis(oasis_obj, strategy, nsel=nsel, neig=neig)
    else:
        raise ValueError('Selected strategy is unknown: '+str(strategy))