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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 _update_dict(self, to_dict, from_dict):
 """ Recursively merges the fields for two dictionaries. Args: to_dict (dict):
 The dictionary onto which the merge is executed. from_dict (dict):
 The dictionary merged into to_dict """

        for key, value in from_dict.items():
            if key in to_dict and isinstance(to_dict[key], dict) and \
                    isinstance(from_dict[key], dict):
                self._update_dict(to_dict[key], from_dict[key])
            else:
                to_dict[key] = from_dict[key]