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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 explicit_singular_entities(self, tax_benefit_system, input_dict):
 """ Preprocess ``input_dict`` to explicit entities defined using the single-entity shortcut Example: {'persons': {'Javier': {}, }, 'household': {'parents': ['Javier']}} ) """


        singular_keys = set(input_dict).intersection(tax_benefit_system.entities_by_singular())
        if not singular_keys:
            return input_dict

        result = {
            entity_id: entity_description
            for (entity_id, entity_description) in input_dict.items()
            if entity_id in tax_benefit_system.entities_plural()
            }  # filter out the singular entities

        for singular in singular_keys:
            plural = tax_benefit_system.entities_by_singular()[singular].plural
            result[plural] = {singular: input_dict[singular]}

        return result