<｜begin▁of▁sentence｜>### Instruction:
As an emergency medical responder, you respond to a call from a community center where several individuals have reported feeling dizzy and disoriented after a recent power outage. Upon arrival, the center's staff provides you with a list of affected individuals along with their respective locations within the building: [(0, 1), (0, 2), (1, 2), (2, 3)]. You need to create a visual representation of the building layout to better understand the situation.

You wonder if there's a way to use the hospital's mapping software along with their imaging tools, such as the Mapping API and the Cairo library, to quickly generate a graphical representation of the building layout, which you can then use to plan your response. Once the visual representation is ready, you can share it with your medical team and other emergency response units.

How can you take advantage of the Mapping API and the Cairo library to create a visual representation of the building layout, and then save it as an image file, 'building_layout.png', to effectively coordinate the response efforts?
### Response:
import igraph as ig
import cairo

# Initialize the graph
edges = [(0, 1), (0, 2), (1, 2), (2, 3)]
g = ig.Graph(edges=edges)

# Create a Cairo image surface to draw to
surface = cairo.ImageSurface(cairo.FORMAT_ARGB32, 400, 400)
ctx = cairo.Context(surface)

# Initialize a CairoGraphDrawer object
drawer = ig.CairoGraphDrawer(ctx)

# Draw the graph onto the Cairo context
# Note: The layout is calculated automatically if not provided.
drawer.draw(g)

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