What are the "options" for "save_variable_instances"?

[futuremotiondev]

"""
Save all instances of a variable font to specified directory in one or more format(s).

:param dirpath: The dirpath
:type dirpath: The directory path where the instances will be saved.
:param woff2: Whether to save instances also in WOFF2 format. Default is True.
:type woff2: bool
:param woff: Whether to save instances also in WOFF format. Default is True.
:type woff: bool
:param overwrite: Whether to overwrite existing files in the directory. Default is True.
:type overwrite: bool
:param options: Additional options to be passed to the instancer when generating static instances.
:type options: dictionary

:returns: A list containing dictionaries for each saved instance. Each dictionary
    includes 'instance' (containing instance metadata) and 'files' (a dictionary
    with file formats as keys and file-paths as values).

:raises TypeError: If the font is not a variable font.
"""

saved_fonts = font.save_variable_instances(dirpath, woff2=True, woff=True, overwrite=True, **options)

Specifically :type options: dictionary

Where can I find these possible options? Thanks.

[fabiocaccamo]

Here the fontTools instancer options that can be customized:
https://github.com/fabiocaccamo/python-fontbro/blob/main/fontbro/font.py#L1611-L1613

Here the fontTools instantiateVariableFont method for reference:
https://github.com/fonttools/fonttools/blob/main/Lib/fontTools/varLib/instancer/__init__.py#L1219