<｜begin▁of▁sentence｜>### Instruction:
As a network administrator, you are tasked with visualizing a clustering result using networkx and then saving it as a PNG file. Given a vertex dendrogram of a tree graph representing a network with 10 nodes, how can you achieve this using the functionality provided by the networkx library?
### Response:
import igraph as ig
from igraph.drawing.cairo import CairoDendrogramDrawer
from igraph.drawing import BoundingBox
import cairo

# Create a toy dendrogram
clustering = ig.VertexDendrogram(ig.Graph.Tree(10, 2),
                               [0] * 2 + [1] * 8)
dendrogram = clustering.as_clustering()

# Set up Cairo surface and context
surface = cairo.ImageSurface(cairo.FORMAT_ARGB32, 600, 400)
context = cairo.Context(surface)

# Create a CairoDendrogramDrawer object
drawer = CairoDendrogramDrawer(context, bbox=BoundingBox(600, 400))

# Draw the dendrogram
drawer.draw(dendrogram)

# Save the result to a file
surface.write_to_png('dendrogram.png')
<|EOT|>
