In writing the work, SCI papers manuscripts I use scikit learning open source code to perform the machine learning method, when I was learning tutorial, I saw machine learning map on this page, https://scikit-learn.org/stable/tutorial/machine_learning_map/, the tutorial says if the data quantity is less than 50, should get more data, so I added these words in my manuscript "in general machine learning the required minimum number of samples of 50", however, I did not find in the website or the resources accordingly, I was asked to provide a source of expression (the official website or refer to a particular text expression), so I seek help from all the people, urgent! Trouble kind help!