def list_of_vars(arg_plot):
lovs = [[[var for var in svars.split('<STR_LIT:U+002C>') if var]<EOL>for svars in pvars.split('<STR_LIT:.>') if svars]<EOL>for pvars in arg_plot.split('<STR_LIT:->') if pvars]<EOL>lovs = [[slov for slov in lov if slov] for lov in lovs if lov]<EOL>return [lov for lov in lovs if lov]<EOL>
Construct list of variables per plot.

    Args:
        arg_plot (str): string with variable names separated with
            ``_`` (figures), ``.`` (subplots) and ``,`` (same subplot).
    Returns:
        three nested lists of str

        - variables on the same subplot;
        - subplots on the same figure;
        - figures.