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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 hash(self, rtdc_ds):
 """Used for identifying an ancillary computation The data columns and the used configuration keys/values are hashed. """

        hasher = hashlib.md5()
        # data columns
        for col in self.req_features:
            hasher.update(obj2str(rtdc_ds[col]))
        # config keys
        for sec, keys in self.req_config:
            for key in keys:
                val = rtdc_ds.config[sec][key]
                data = "{}:{}={}".format(sec, key, val)
                hasher.update(obj2str(data))
        return hasher.hexdigest()