<｜begin▁of▁sentence｜>### Instruction:
Given a simple ring graph with 5 vertices, how can you customize the drawing of each vertex by altering properties such as shape, size, and color? Use the AbstractVertexDrawer.draw method to customize these properties before saving the plot as an image.
### Response:
from igraph import Graph, plot
from igraph.drawing import Plot
from igraph.drawing.graph import DefaultGraphDrawer

def custom_vertex_drawer(vertex, coords, visual_vertex):
    visual_vertex['shape'] = 'circle'
    visual_vertex['size'] = 20
    visual_vertex['color'] = 'blue'
    return coords, visual_vertex

g = Graph.Ring(5)
plot = Plot('./custom_ring_plot.png', bbox=(300, 300), background='white')
plot.add(g, layout=g.layout_circle(), vertex_drawer=custom_vertex_drawer)
plot.redraw()
print('Custom ring plot with modified vertex properties has been saved.')
<|EOT|>
