I want to use graphs.planar_graphs (which is based on plantri) to generate 1000 planar graphs of a certain size (e.g. 50 vertices), i.e. I want to use the iterator exactly 1000 times and not until it has created all possible solutions. How can I do this with graphs.planar_graphs, since this is an iterator that just creates all possible planar graphs on 50 vertices (which is a lot more than I need and also too computationally expensive)?