If my interpretation is correct:

human_eyes.input(emit_light(580))

-> ((0.5, 0.5, 0), "Pure Yellow")

human_eyes.input(emit_light([[650, 0.3456], [550, 0.4567], [450, 0.0]]))

-> ((0.5, 0.5, 0), "Pure Yellow")

human_eyes.input(emit_light([[670, 0.00625], [640, 0.03125], ... [450, 0.0]]))

-> ((0.5, 0.5, 0), "Pure Yellow")

... because input is a list but output is a weighted average in a single 3D vector.