<｜begin▁of▁sentence｜>### Instruction:
Given a graph layout, can you calculate the centroid of the layout, which is the arithmetic mean of all points in the layout? You'll need to use the 'centroid' function of the 'Layout' class from the igraph library.
### Response:
from igraph import Graph, Layout

# Assuming we have a graph already
graph = Graph.Famous('Zachary')  # Using a famous graph for demonstration
layout = graph.layout('kk')  # Kamada-Kawai layout to spread vertices for visualization
centroid = layout.centroid()

print('Centroid of the layout:', centroid)
<|EOT|>
