一个小的教程程序有段代码不明白什么意思

这是一个简单的建立名字索引的程序，我想红色字体的代码有什么用呢，我感觉加不加它们结果都是一样的
Python code

data={}
data['first']={'duncan': ['duncan Lie deng']}
data['middle']={'Lie': ['duncan Lie deng']}
data['last']={'deng': ['duncan Lie deng']}

people={}
full_name='Simth Will'

names = full_name.split()
if len(names)==2: names.insert(1,'')
labels=('first','middle','last')

for label,name in zip(labels,names):
[color=#FF0000]    people=data[label].get(name)
    if people:
        people.append(full_name)
    else:[/color]
        data[label][name]=[full_name]
print data

运行结果：
{'middle': {'': ['Simth Will'], 'Lie': ['duncan Lie deng']}, 'last': {'Will': ['Simth Will'], 'deng': ['duncan Lie deng']}, 'first': {'Simth': ['Simth Will'], 'duncan': ['duncan Lie deng']}}

不好意思，没有编辑好
people=data[label].get(name)
  if people:
  people.append(full_name)
  else:
这一段

看的晕头转向的，你的people是字典怎么能append？

这也是我不太理解的