Suggested by @MostAwesomeDude in [this](https://github.com/satwikkansal/wtfPython/issues/1) issue.

x = True

y = False

**Output:**

>>> not x == y

>>> x == not y

File "<input>", line 1

x == not y

^

SyntaxError: invalid syntax

* Operator precedence affects how an expression is evaluated, and `==` operator has higher precedence than `not` operator in Python.

* So `not x == y` is equivalent to `not (x == y)` which is equivalent to `not (True == False)` finally evaluating to `True`.

* But `x == not y` raises a `SyntaxError` because it can be thought of being equivalent to `(x == not) y` and not `x == (not y)` which you might have expected at first sight.

* The parser expected the `not` token to be a part of the `not in` operator (because both `==` and `not in` operators have same precedence), but after not being able to find a `in` token following the `not` token, it raises a `SyntaxError`.