If the author had gone through the documentation or even asked around the mailing list, the first thing he would learnt was to expect common packages to implement "common-sensical" interfaces.For e.g: when I first used os.File, my first thought was, "Oh, it must be implementing the io.Reader in there somewhere, since you know, its a File package". Next thing was to look up the os.File and io.Reader package and confirming it. In time maybe this "common sense" can be further improved by having a hand-holding IDE.