def __add__(self, other):
        if not isinstance(other, Counter):
            return NotImplemented
        result = Counter()
        for elem in set(self) | set(other):
            newcount = self[elem] + other[elem]
            if newcount > 0:
                result[elem] = newcount
        return result
Add counts from two counters.
dataset/ETHPy150Open dbcli/pgcli/pgcli/packages/counter.py/Counter.__add__