Variable

未定义的 variable

>>> len(abc)
Traceback (most recent call last):
  File "<console>", line 1, in <module>
NameError: name 'abc' is not defined

>>> a = {}
>>> a["s"]
Traceback (most recent call last):
  File "<console>", line 1, in <module>
KeyError: 's'

>>> fun()
Traceback (most recent call last):
  File "<console>", line 1, in <module>
NameError: name 'fun' is not defined

>>> a = None
>>> a()
Traceback (most recent call last):
  File "<console>", line 1, in <module>
TypeError: 'NoneType' object is not callable

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