<｜begin▁of▁sentence｜>### Instruction:
As a chemical technician conducting experiments in the laboratory to assist chemists or chemical engineers in research and development, you have been tasked with creating a visual representation of a molecular structure using the CairoArrowEdgeDrawer to visually depict the bonds between atoms. The molecular structure is a simple tree graph with three levels and each atom having at most two bonds. Your goal is to accurately represent this graph as a visual image using the CairoArrowEdgeDrawer's capabilities for drawing edges with arrows.
### Response:
from igraph import Graph
from igraph.drawing import Plot
from igraph.drawing.edge import CairoArrowEdgeDrawer

g = Graph.Tree(3, 2) # A simple tree graph
plot = Plot()
plot.add(g, edge_drawer=CairoArrowEdgeDrawer())
plot.save('tree_graph.png')
<|EOT|>
