Function to infer a 4-node hybridization cycle using the phylogenetic invariants method
(Wu and Solis-Lemus, 2022)
Input:
    cf: DataFrame object with the concordance factor table (first 4 columns should be taxon names, last 3 columns should be cf values)
    m: the number of optimal phylogenetic networks returned
    output_filename: a file name for the output file (or "phylo_diamond.txt" by default)
output:
    top m optimal phylogenetic networks in a Dict object

Function to infer a 4-node hybridization cycle using the phylogenetic invariants method
(Wu and Solis-Lemus, 2022)
Input:
    gene_trees_filename: textfile with gene trees (one per row) in parenthetical format
    m: the number of optimal phylogenetic networks returned
    output_filename: a file name for the output file (or "phylo_diamond.txt" by default)
output:
    top m optimal phylogenetic networks in a Dict object