Yurttas/PL/SL/python/docs/core-python-programming/doc/20/lib/module-main.html
3.26 __main__ -- Top-level script environment
This module represents the (otherwise anonymous) scope in which the interpreter's main program executes -- commands read either from standard input, from a script file, or from an interactive prompt. It is this environment in which the idiomatic ``conditional script'' stanza causes a script to run:
if __name__ == "__main__":
main()
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