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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 _read_dict(self, data_dict, layer=None, source=None):
 """Load a dictionary into the ConfigTree. If the dict contains nested dicts then the values will be added recursively. See module docstring for example code. Parameters data_dict : dict source data layer : str layer to load data into. If none is supplied the outermost one is used source : str Source to attribute the values to """

        for k, v in data_dict.items():
            self._set_with_metadata(k, v, layer, source)