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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 _data(self):
 """ Cached data built from instance raw _values as a dictionary. """

        d = {}

        # Iterate all keys and values
        for k, v in self._row_values.items():
            # Split related model fields
            attrs = k.rsplit('__', 1)

            # Set value depending case
            if len(attrs) == 2:
                # Related model field, store nested
                fk, fn = attrs
                if fk not in d:
                    d[fk] = {}
                d[fk][fn] = v

            else:
                # Own model field, store directly
                d[k] = v

        # Return (+cache) data
        return d