If you picked the seeds, could you describe them, or post a photo? Was the original plant wild or cultivated, and where was it growing? Are the flowers fragrant? More info would be helpful. At a guess, it looks like a member of genus Canavalia.

it was growing on a fence near the entrance of an underground parking lot. it's not a wild species since I don't know anything close to it growing here in the wild, but it wasn't cultivated for food since there were only a few plants there. the flowers are a bit fragrant.

Where was this parking lot in the world?

which country?