Specs throws an error

I have a subplot with 13 rows and 1 column.When I try giving specs,it shows an error like this:
The ‘specs’ argument to make_subplots must be a 2D list of dictionaries with dimensions 13x1.
How can I solve this?This is my original code

specs = [[{'type': 'treemap', 'rowspan': 1}]*13]