<｜begin▁of▁sentence｜>### Instruction:
As an occupational therapist, suppose you are working with a client who is learning about network visualization and wants to create a customized shape for a single vertex in a graph. They are interested in using the ShapeDrawer.draw_path method to override the default shape with a circle and then rendering the graph on a Cairo context. How can you guide your client through this process to help them achieve their goal of creating a personalized graph visualization?
### Response:
from igraph import Graph, plot
from igraph.drawing.shapes import CircleDrawer
import cairo

g = Graph()
g.add_vertices(1)

# Custom drawing function for a circle shape
def draw_circle(ctx, center_x, center_y, width, height=None, **kwargs):
    if height is None:
        height = width
    ctx.arc(center_x, center_y, width / 2, 0, 2 * 3.14159)
# Override the draw_path method with our custom drawing function
CircleDrawer.draw_path = staticmethod(draw_circle)

surface = cairo.ImageSurface(cairo.FORMAT_ARGB32, 400, 400)
ctx = cairo.Context(surface)

# Using igraph to draw the graph with our custom circle drawer
plot(g, target=ctx)

# Save the image
crop = (0, 0, 200, 200)
surface.write_to_png('custom_circle_graph.png')
<|EOT|>
