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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 load_nb(cls, inline=True):
 """ Initialize matplotlib backend """

        import matplotlib.pyplot as plt
        backend = plt.get_backend()
        if backend not in ['agg', 'module://ipykernel.pylab.backend_inline']:
            plt.switch_backend('agg')