def resize_graph(dot, size_per_element=0.15, min_size=12):
    """Resize the graph according to how much content it contains.

    Modify the graph in place.
    """
    num_rows = len(dot.body)
    content_size = num_rows * size_per_element
    size = max(min_size, content_size)
    size_str = str(size) + ',' + str(size)
    dot.graph_attr.update(size=size_str)
