def get_click_position(impressions: List[str], click: str) -> int:
    """Returns the position of the clicked item based on the array of impressions."""
    try:
        return impressions.index(click) + 1
    except ValueError:
        return -1

    
# Unit test: Row level
@pytest.mark.parametrize('impressions,click,expected',
                         [(['i1', 'i2', 'i3', 'i4'], 'i1', 1),
                          (['i1', 'i2', 'i3', 'i4'], 'i3', 3),
                          (['i1', 'i2', 'i3', 'i4'], None, -1),
                          (['i1', 'i2', 'i3', 'i4'], 'NA', -1)])
def test_get_click_position(impressions, click, expected):
    assert get_click_position(impressions, click) == expected