On windows, you should run multiprocessing functions insideif __name__ == "__main__"
(doc1, doc2). So, try this:
import multiprocessing
def doCalc(year):
return year*year
yearlist = [1,2,3,4]
print(yearlist)
if __name__ == '__main__':
pool = multiprocessing.Pool(4)
pool.map(doCalc, yearlist)