<｜begin▁of▁sentence｜>### Instruction:
Given a directed graph with vertices {0, 1, 2, 3} and edges {(0, 1), (1, 0), (1, 2), (2, 3)}, can you use the dyad_census function to count how many pairs of vertices are in mutual, asymmetric, and null relationships?
### Response:
from igraph import Graph

# Create a directed graph with some edges
directed_graph = Graph(directed=True)
directed_graph.add_vertices(4)
directed_graph.add_edges([(0, 1), (1, 0), (1, 2), (2, 3)])

# Use dyad_census to classify pairs of vertices
dyad_census = directed_graph.dyad_census()

# Print the results
print(f'Mutual: {dyad_census[0]}, Asymmetric: {dyad_census[1]}, Null: {dyad_census[2]}')
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