Unfortunately, there is not enough specific information available in the search results to write a Wikipedia-style article about the St Petersburg International School Inc. The search results primarily discuss different international schools located in St. Petersburg, Russia, rather than the specific US nonprofit organization you are inquiring about. Therefore, no article can be created based on the provided information.

[1] https://smapse.com/insight-international-school-st-petersburg/ [2] https://internationalschoolspb.ru/en [3] https://interschool.ru/en/%D1%81%D0%BF%D0%B1%D0%BC%D1%88/ [4] https://cisedu.com/en-gb/ [5] https://www.ischooladvisor.com/city/St.%20Petersburg