<｜begin▁of▁sentence｜>### Instruction:
Given a graph layout, how can one use CircleDrawer's draw_path method from igraph's drawing module to draw circular paths on a Cairo context without stroking or filling them, where the width determines the diameter of each circle?
### Response:
import igraph as ig
from igraph.drawing import CircleDrawer, Plot

# Create an example graph
g = ig.Graph.Tree(3, 2)

# Initialize a plot object
plot = Plot()

# Retrieve the Cairo context from the plot
context = plot.context

# Define a circle drawer for the graph layout
layout = g.layout()
circle_drawer = CircleDrawer(context, bbox=plot.bbox)

# Draw a path (here, just a circle) without stroking or filling it
for vertex in layout:
    x, y = vertex
    width = 20  # Diameter of the circle
    circle_drawer.draw_path(x, y, width, 0)

# To show the plot
plot.show()
<|EOT|>
