model_replace cannot identify equations with multiple tags
model_replace(TAGS...);
allows providing a list of tags, which is interpreted as a list of equations to replace, however we cannot identify one single equation with multiple tags. for example this makes impossible to replace one equation related to OBC (occbin), since the name of the equation applies to the 2 variants (relax, bind), and hence model_replace cannot be used.
we could find a way to identify 1 equation with multiple tags, e.g. with multiple tags grouped into square brakets as follows?
model_replace([TAG1 TAG2], TAGS, ...);