<｜begin▁of▁sentence｜>### Instruction:
As a network analyst working in a research lab, I need to visualize a directed graph representing a complex network of interactions between different proteins. I am using the igraph library in Python to create the visualization, and I want to customize the arrow sizes for the edges to emphasize the strength of the interactions. How can I achieve this customization using the igraph library?
### Response:
import igraph as ig

# Create a directed graph
g = ig.Graph(directed=True)

# Add vertices
g.add_vertices(3)

# Add directed edges
g.add_edges([(0, 1), (1, 2)])

# Initialize plot
plot = ig.Plot()

# Add the graph to the plot
plot.add(g)

# Customize the arrow sizes
plot.redraw()
for edge in plot.objects[0]._context:
    edge.set_arrow_sizes(15)

# Save the plot to a file
plot.save('directed_graph_with_custom_arrows.png')
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