Error in limma::makeContrasts at node_color_per_de()

[mpaya]

After following the pipeline in hipathia documentation, at the step of Pathway comparison I sumbled into this error:

> colors_de <- node_color_per_de(results, pathways, sample_group, "Tumour, NOS", "Control")
Error in limma::makeContrasts(contrasts = expdes, levels = design) : 
  The levels must by syntactically valid names in R, see help(make.names).

This error indicates how to fix this issue with make.names(). This function would create "Tumour..NOS". But to apply at this step over results is not too straight-forward. Maybe interesting to consider indicating at the beginning that sample group names have to follow some rules to avoid this error.