Modified method for extracting unique indices from obs or par dfs in _get_tpl_or_ins_df().
Using list(zip(()) to hopefully better preserve dtype when index cols are mixed type.
Significant speed up means that we can use the same method (order preserving) for obs and pars.
coverage: 79.743% (+0.06%) from 79.687% when pulling 2f22e0eb87658dd2269b687497a0b83f8a427623 on briochh:hotfix_obsidxtypes into d37c2b45c5e46ed69b405ef5a8972ee5d00bdc91 on pypest:develop.
Modified method for extracting unique indices from obs or par dfs in _get_tpl_or_ins_df().
Using list(zip(()) to hopefully better preserve dtype when index cols are mixed type. Significant speed up means that we can use the same method (order preserving) for obs and pars.