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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 lock(self):
 """Returns a JSON representation of the Pipfile."""

        data = self.data
        data['_meta']['hash'] = {"sha256": self.hash}
        data['_meta']['pipfile-spec'] = 6
        return json.dumps(data, indent=4, separators=(',', ': '))