Heatmap normalization?

[bhavyaac]

Hello! If I understand correctly, the heatmaps produced by CellphoneDB plot the number of significant interactions found between clusters.
Is this value normalized based on the number of cells in a cluster? If not, do you think this is an issue? (i.e. would you expect to see more interactions between two large clusters as compared to two smaller ones?)
Please let me know what you think. Thank you!