In the variable lesson, I don't understand why the word "not" is in another color and rejected in "spaces are not allowed

Answer 1

To get help from the community you should put your code in playground and link it here. Thanks!

Answer 2

The highlighting of the word 'not' is easy to clarify: It's a keyword, the boolean logic-'not', the equivalent of '!'. Keywords are always highlighted. What the space-part of your question means I also don't understand without a piece of code.