Python 中的顶级语句是什么？

在 Python 指南的章节中项目结构 http://docs.python-guide.org/en/latest/writing/structure.html中，“高层声明”一词被多次提及。我不确定这到底指的是什么。我的猜测是，在加载模块后立即触发的任何函数或类方法之外发生的任何变量声明。它是否正确？它还包括模块的import声明？

它不仅仅是变量声明（而且根本没有任何变量声明）。它几乎是从缩进级别 0 开始的任何内容。

import sys         # top-level

3 + 4              # top-level

x = 0              # top-level

def f():           # top-level
    import os      # not top-level!
    return 3       # not top-level

if x:              # top-level
    print 3        # not top-level
else:
    print 4        # not top-level, but executes as part of an if statement
                   # that is top-level

class TopLevel(object): # top-level
    x = 3          # not top-level, but executes as part of the class statement
    def foo(self): # not top-level, but executes as part of the class statement
        print 5    # not top-level