Thanks Chris and Ian, Your suggested experiments and explanations have really provided some good insights, something Tutorial didn't indicate.
Ian's explanation reminds me of #ifndef _HEADER_H_ #define _HEADER_H_ ... #endif // _HEADER_H_ in C/C++, and I can draw parallels to why subsequent attempts to import same module shouldn't result in flagging an error, and need for multiple imports to refer to same information. -- https://mail.python.org/mailman/listinfo/python-list