Alicia owns a solar powered home. Alicia’s neighbor, Bonnie,…

Alicia owns a solar powered home. Alicia’s neighbor, Bonnie, lives next door and is constructing a new home. Bonnie has agreed not to build her new home more than 2 stories high close to the boundary line Alicia and Bonnie share with each other, so that Bonnie’s home will not prevent the obstruction of sunlight to Alicia’s solar powered home. Is this an affirmative or negative easement?