<｜begin▁of▁sentence｜>### Instruction:
In a simple undirected graph where each node is associated with a rectangle having width 10 and height 20, how would you use a custom __hash__ method to ensure each rectangle is unique and count the number of unique rectangles?
### Response:
import networkx as nx

# Create a simple graph
G = nx.Graph()
G.add_edges_from([(1, 2), (1, 3), (3, 4), (2, 5)])

# Use the __hash__ method from a hypothetical Rectangle module
# Assuming you have a NodeRectangle class that you can associate with graph nodes
class NodeRectangle:
    def __init__(self, width, height):
        self.width = width
        self.height = height
    def __hash__(self):
        return hash((self.width, self.height))

# Assigning rectangles to each node in the graph
for node in G.nodes():
    G.nodes[node]['rect'] = NodeRectangle(width=10, height=20)

# Creating a set to store unique rectangles based on their hash
unique_rectangles = set()
for node, data in G.nodes(data=True):
    unique_rectangles.add(data['rect'])

# Outputting the number of unique rectangles
print('Number of unique rectangles:', len(unique_rectangles))
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