import sys

#Statement has no effect (4 statements, 3 of which are violations)

"Not a docstring" # This is acceptable as strings can be used as comments.

len

sys.argv + []

3 == 4

#The 'sys' statements have an effect

try:

sys

except:

do_something()

def exec_used(val):

exec (val)

#This has an effect:

def effectful(y):

[x for x in y]

#Not a redundant assignment if a property.

class WithProp(object):

@property

def x(self):

return self._x

@prop.setter

def set_x(self, x):

side_effect(x)

self._x = x

def meth(self):

self.x = self.x

#Accessing a property has an effect:

def prop_acc():

p = WithProp()

p.x

def mydecorator(func):

return property(fget=func)

class X(object):

@mydecorator

def deco(self):

pass

def func(self):

pass

x = X()

x.deco

x.deco + 2

#No effect

x.func

#Cannot infer what attribute is, so be conservative

x.thing

other_thing.func

#Name Error

try:

unicode

except NameError:

#Python 3

unicode = str

try:

ascii

except NameError:

#Python 2

def ascii(obj):

pass

#Overridden operator. yuck.

class Horrible(object):

def __add__(self, other):

fire_missiles_at(other)

def __lt__(self, other):

fire_guns_at(other)

def possible_fps(x):

h = Horrible()

h + "innocent bystander"

h < "upstanding citizen"

x - 3 #True positive

# Forgotten raise.

def do_action_forgotten_raise(action):

if action == "go":

start()

elif action == "stop":

stop()

else:

ValueError(action)

def do_action(action):

if action == "go":

start()

elif action == "stop":

stop()

else:

raise ValueError(action)

#Python 2 print

print >> out, message