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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 prov(self):
 """ Extracts provenance information from the study for storage alongside generated derivatives. Typically for reference purposes only as only the pipeline workflow, inputs and outputs are checked by default when determining which sessions require reprocessing. Returns ------- prov : dict[str, *] A dictionary containing the provenance information to record for the study """

        # Get list of repositories where inputs to the study are stored
        input_repos = list(set((i.repository for i in self.inputs)))
        inputs = {}
        for input in self.inputs:  # @ReservedAssignment
            inputs[input.name] = {
                'repository_index': input_repos.index(input.repository)}
            if input.frequency == 'per_study':
                inputs[input.name]['names'] = next(input.collection).name
            elif input.frequency == 'per_subject':
                inputs[input.name]['names'] = {i.subject_id: i.name
                                               for i in input.collection}
            elif input.frequency == 'per_visit':
                inputs[input.name]['names'] = {i.visit_id: i.name
                                               for i in input.collection}
            elif input.frequency == 'per_session':
                names = defaultdict(dict)
                for item in input.collection:
                    names[item.subject_id][item.visit_id] = item.name
                # Convert from defaultdict to dict
                inputs[input.name]['names'] = dict(names.items())
        return {
            'name': self.name,
            'type': get_class_info(type(self)),
            'parameters': {p.name: p.value for p in self.parameters},
            'inputs': inputs,
            'environment': self.environment.prov,
            'repositories': [r.prov for r in input_repos],
            'processor': self.processor.prov,
            'subject_ids': self.subject_ids,
            'visit_ids': self.visit_ids}