%%% %%% Layer activity %%% \myprogram{{layer\_activity.py}} {compute the activity of the layers of a multiplex, i.e. the number of active nodes on each layer.} {$<$layer1$>$ [$<$layer2$>$ ...]} \mydescription{Compute and print on output the activity of the layers of a multiplex network, where the layers are given as input in the files \textit{layer1}, \textit{layer2}, etc. Each file contains the (undirected) edge list of a layer, and each line is in the format: \hspace{0.5cm}\textit{src\_ID} \textit{dest\_ID} where \textit{src\_ID} and \textit{dest\_ID} are the IDs of the two endpoints of an edge.} \myreturn{A listof lines, where the n-th line is the value of activity of the n-th layer, starting from \textbf{0}.} \myreference{\refcorrelations}