<｜begin▁of▁sentence｜>### Instruction:
Given a graph instance from igraph where the internal structure and nodes are already defined, how would you list all the triangles in the graph, where each triangle is a trio of connected vertices?
### Response:
from igraph import GraphBase

# Create a graph instance (GraphBase is generally not used directly)
g = GraphBase() # Example initialization (GraphBase is abstract, so normally another constructor is used.)
triangles = g.list_triangles()

# Print the list of triangles
for triangle in triangles:
    print(triangle)
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