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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 _loadable_models():
 """A dictionary of loadable PyPhi models. These are stored in this function (instead of module scope) to resolve circular import issues. """

    classes = [
        pyphi.Direction,
        pyphi.Network,
        pyphi.Subsystem,
        pyphi.Transition,
        pyphi.labels.NodeLabels,
        pyphi.models.Cut,
        pyphi.models.KCut,
        pyphi.models.NullCut,
        pyphi.models.Part,
        pyphi.models.Bipartition,
        pyphi.models.KPartition,
        pyphi.models.Tripartition,
        pyphi.models.RepertoireIrreducibilityAnalysis,
        pyphi.models.MaximallyIrreducibleCauseOrEffect,
        pyphi.models.MaximallyIrreducibleCause,
        pyphi.models.MaximallyIrreducibleEffect,
        pyphi.models.Concept,
        pyphi.models.CauseEffectStructure,
        pyphi.models.SystemIrreducibilityAnalysis,
        pyphi.models.ActualCut,
        pyphi.models.AcRepertoireIrreducibilityAnalysis,
        pyphi.models.CausalLink,
        pyphi.models.Account,
        pyphi.models.AcSystemIrreducibilityAnalysis
    ]
    return {cls.__name__: cls for cls in classes}