

def __add__(self, other):
    if com.is_list_like(other):
        warnings.warn("using '+' to provide set union with Indexes is deprecated, use '|' or .union()", FutureWarning, stacklevel=2)
    if isinstance(other, Index):
        return self.union(other)
    return Index((np.array(other) + other))

dataset/ETHPy150Open pydata/pandas/pandas/indexes/base.py Index.__add__/VarMisuse@63/102 `self`->`other`