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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 _merge(self, a, b):
 """Merges a into b."""

        for k, v in a.items():
            if isinstance(v, dict):
                item = b.setdefault(k, {})
                self._merge(v, item)
            elif isinstance(v, list):
                item = b.setdefault(k, [{}])
                if len(v) == 1 and isinstance(v[0], dict):
                    self._merge(v[0], item[0])
                else:
                    b[k] = v
            else:
                b[k] = v
        return b