Why is this an issue?
There are several reasons for a function or a method not to have a body:
- It is an unintentional omission, and should be fixed to prevent an unexpected behavior in production.
- It is not yet, or never will be, supported. In this case an exception should be thrown.
- The method is an intentionally-blank override. In this case a nested comment should explain the reason for the blank override.
Noncompliant code example
def myfunc1(foo="Noncompliant"):
pass
class MyClass:
def mymethod1(self, foo="Noncompliant"):
pass
Compliant solution
def myfunc1():
pass # comment explaining why this function is empty
def myfunc2():
raise NotImplementedError()
def myfunc3():
"""
Docstring explaining why this function is empty.
"""
class MyClass:
def mymethod1(self):
pass # comment explaining why this function is empty
def mymethod2(self):
raise NotImplementedError()
def mymethod3(self):
"""
Docstring explaining why this method is empty. Note that this is not recommended for classes
which are meant to be subclassed.
"""
Exceptions
No issue will be raised when the empty method is abstract and meant to be overriden in a subclass, i.e. it is decorated with
abc.abstractmethod, abc.abstractstaticmethod, abc.abstractclassmethod or abc.abstractproperty.
Note however that these methods should normally have a docstring explaining how subclasses should implement these methods.
import abc
class MyAbstractClass(abc.ABC):
@abc.abstractproperty
def myproperty(self):
pass
@abc.abstractclassmethod
def myclassmethod(cls):
pass
@abc.abstractmethod
def mymethod(self):
pass
@abc.abstractstaticmethod
def mystaticmethod():
pass
