BUG: unnecessary repetition of variable in explode test
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---

In the test `test_typical_usecase` in `series/methods/test_explode.py` there's 

```python
def test_typical_usecase():

    df = pd.DataFrame(
        [{"var1": "a,b,c", "var2": 1}, {"var1": "d,e,f", "var2": 2}],
        columns=["var1", "var2"],
    )
    exploded = df.var1.str.split(",").explode()
    exploded
    result = df[["var2"]].join(exploded)
    expected = pd.DataFrame(
        {"var2": [1, 1, 1, 2, 2, 2], "var1": list("abcdef")},
        columns=["var2", "var1"],
        index=[0, 0, 0, 1, 1, 1],
    )
    tm.assert_frame_equal(result, expected)
```

#### Problem description

The variable `exploded` is called unnecessary.

