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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 _get_activation(self, act):
 """Get activation block based on the name. """

        if isinstance(act, str):
            if act.lower() == 'gelu':
                return GELU()
            else:
                return gluon.nn.Activation(act)
        assert isinstance(act, gluon.Block)
        return act