machine learning framework, provides a function to read training data in parallel (fork-join style) and generate a mini-batch from them. 4 A part of process of MultiprocessIterator (“fetch data” part). file reader process solve the file path read the file convert the file into nump .ndarra inde list data1, data2, data3... [1, 2, 3, 4, 5, 6, 7, 8] mini-batch q e e (on memor ) mini-batch file reader process solve the file path read the file convert the file into nump .ndarra file reader process solve the file path read the file convert the file into nump .ndarra