<｜begin▁of▁sentence｜>### Instruction:
As a network analysis professional, you may encounter situations where you need to visualize a directed graph specified in a GML file. One common requirement is to use igraph's LightToDarkEdgeDrawer to draw edges with a gradient from light to dark, representing the direction of the edge. This can be particularly useful for illustrating the flow or hierarchy in a network.
### Response:
import igraph as ig
import cairo

# Load graph and prepare cairo surface
filename = 'network.gml'
g = ig.Graph.Read_GML(filename)
surface = cairo.ImageSurface(cairo.FORMAT_ARGB32, 800, 600)
ctx = cairo.Context(surface)

# Layout for the graph
g_layout = g.layout('kk')  # Kamada-Kawai layout

# Configure visual styles for the graph
visual_style = {}
visual_style['vertex_size'] = 20
visual_style['vertex_color'] = 'white'
visual_style['vertex_label'] = g.vs['label']
visual_style['edge_curved'] = False
visual_style['layout'] = g_layout
visual_style['margin'] = 50

# Prepare edge drawer
edge_drawer = ig.drawing.LightToDarkEdgeDrawer(ctx)

# Draw the graph with light to dark edges
for edge in g.es:
    start_coord = g_layout[edge.source]
    end_coord = g_layout[edge.target]
    edge_drawer.draw_directed_edge(start_coord, end_coord, None)

# Save to a file
surface.write_to_png('light_to_dark_edges.png')
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