I'm afraid you missed the joke ;-) While you believe spaces are required on both sides of an em dash, there is no consensus on this point. For example, most (but not all) American authorities say /no/ spaces should be used. That's the joke. In writing a line about "only one way to do it", I used a device (em dash) for which at least two ways to do it (with spaces, without spaces) are commonly used, neither of which is obvious -- and deliberately picked a third way just to rub it in. This will never change ;-)

The language was designed with this idea in mind, in that it “doesn't try to tell the programmer how to program.”

This motto has been very much discussed in the Perl community, and eventually extended to There’s more than one way to do it, but sometimes consistency is not a bad thing either (TIMTOWTDIBSCINABTE, pronounced Tim Toady Bicarbonate).[1] In contrast, part of the Zen of Python is, "There should be one— and preferably only one —obvious way to do it."