Return table in format that can convert to multilayer dataframe

[titipata]

We have a function to parse table from Pubmed OA subsets. However, right now, it returns only tables that have one layer (only list of values per one column).

However, tables from Pubmed OA could be multilayers which we currently discard those rows of column names. I would like to have function that parse those table in a format that we can use pandas to convert it right away (e.g. JSON format or a list that we can convert it easily)