ValueError: Can't cast from structure to non-structure

[lime-n]

I'm trying to convert a set of coordinates but I get the following error:

Can't cast from structure to non-structure, except if the structure only has a single field.

Here's an example of my code:

test = ((29.976858, -90.410561), (29.971119, -90.407745), (29.950888, -90.076546), (47.252495, -122.439644), (47.272591, -122.47448), (47.646713, -122.347435), (47.657841, -122.350327), (47.615028, -122.319855), (47.650452, -122.35051), (47.651093, -122.347435))

results = rg.search(test)