ValueError: The truth value of an array with more than one element is ambiguous.


```python
            if (self.index_label and
                    isinstance(self.index_label, (list, tuple, np.ndarray,
                                                  Index))):
```
#### Problem description

self.index_label can be an array, list, Index or tuple, but boolean values of arrays are ambiguous. Should be changed to 

            if (self.index_label is not None and
                    isinstance(self.index_label, (list, tuple, np.ndarray,
                                                  Index))):

#### Expected Output

Formatted excel cell

#### Output of ``pandas/io/formats/excel.get_formatted_cells``

<details>
 in get_formatted_cells
    yield cell
 in _format_hierarchical_rows
    if (self.index_label and isinstance(self.index_label, (list, tuple, np.ndarray, Index))):
ValueError: The truth value of an array with more than one element is ambiguous. Use a.any() or a.all()

</details>
