<｜begin▁of▁sentence｜>### Instruction:
Given a famous Petersen graph, can you compute a Kamada-Kawai layout and transform the layout coordinates by rotating it 90 degrees using a custom function with the transform method from igraph's Layout class?
### Response:
from igraph import Graph, Layout
import igraph as ig

def rotate_90_degrees(coords):
    x, y = coords
    return (-y, x)

g = ig.Graph.Famous('petersen')
layout = g.layout('kk')  # Kamada-Kawai layout to start with

# Rotate the layout by 90 degrees
rotated_layout = layout.transform(rotate_90_degrees)
print(rotated_layout.coords)
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