I have a `pandas.Series` of tuples:

```
s = pd.Series([('a','b','c'), ('a','c','b'), ('c','a','b')])

```

and I want to check whether `('a','b','c')` is in `s` (or any other tuple). So: 

```
('a', 'b', 'c') in s

```

returns `False`. However,

```
('a', 'b', 'c') in s.tolist()

```

returns, as expected, `True`. Is there an optimized, pandas' way, of doing it? It feels very non-pythonic to convert to a list.