Why don't we give users a chance to set "page_size" keyword in rest settings?

[sihcpro]

I'm trying to change the page size by the keyword page_size in postman and it didn't work
Then, I found this in the library code:

class PageNumberPagination(BasePagination):
    ...
    # Client can control the page size using this query parameter.
    # Default is 'None'. Set to eg 'page_size' to enable usage.
    page_size_query_param = None
    page_size_query_description = _('Number of results to return per page.')
    ...

Why don't we just set it like:

    page_size_query_param = api_settings.PAGE_SIZE_KEYWORD

And I won't need to create a class that I just set the attribute page_size_query_param.