from collections import ChainMap
 
class DeepChainMap(ChainMap):
    def __getitem__(self, key):
        values = (mapping[key] for mapping in self.maps if key in mapping)
        try:
            first = next(values)
        except StopIteration:
            return self.__missing__(key)
        if isinstance(first, dict):
            return self.__class__(first, *values)
        return first
 
    def __repr__(self):
        return repr(dict(self))
 
a = {'123': {'player': 1,
             'opponent': 2},
     '18': {'player': 10,
            'opponent': 12}
    }
 
 
b = {'123': {'winner': 1},
     '180': {'winner': 2}
    }
 
print(DeepChainMap(a, b))

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