This in turn means it cannot be used as a definite assignment to a variable.

反过又意味着，分部方法不能作为一个明确分配的变量。

youdao

By default, a variable is scoped to the function in which it is first assigned to, or is global if its first assignment occurs outside any function.

默认情况下，变量的范围是变量第一次被分配到的函数的内部，如果它的第一次分配出现在任何函数的外部，那么它就是全局变量。

youdao

Subsequently, its value is set to an order number returned by a custom code action by using a variable assignment action.

随后，它的值会设置为一个顺序号，它是由使用变量分配操作的通用代码所返回的。

youdao

- And here as promised is that other operator -- looks a little weird, but because assignment is already using the equal sign to assign one value on the right to a variable on the left.

在这里正像所承诺的那样，其他的操作-,看起来有点怪异，但是因为“=“已经被用来当赋值运算符了,用来把右边的一个值赋值给左边的变量。

哈佛公开课 - 计算机科学课程节选