Import or not to import classmethod?

Question

I hope this isn't a stupid question but I found some code where they imported classmethod and some code where they don't so there is difference?

I'm using python 3.6 but the code originally I think was for python 2.7 (it used from __builtin__ import)

import unittest
from selenium import webdriver
from builtins import classmethod #original code was from __builtin__ import classmethod 


class HomePageTest(unittest.TestCase):
    @classmethod
    def setUp(cls):
        # create a new Firefox session
        cls.driver = webdriver.Firefox()
        cls.driver.implicitly_wait(30)
        cls.driver.maximize_window()

        # navigate to the application home page
        cls.driver.get("http://demo-store.seleniumacademy.com/")

    def test_search_field(self):
        pass

    #My tests without @classmethod

    @classmethod
    def tearDown(cls):
        # close the browser window
        cls.driver.quit()

if __name__ == '__main__':
    unittest.main(verbosity=2)

Answer 1

Normally you only import builtins or __builtin__ if you also have a variable in your code with the same name as a builtin and also want to access the builtin name. The documentation of the module explains it rather well:

builtins — Built-in objects

This module provides direct access to all ‘built-in’ identifiers of Python; for example, builtins.open is the full name for the built-in function open(). See Built-in Functions and Built-in Constants for documentation.

This module is not normally accessed explicitly by most applications, but can be useful in modules that provide objects with the same name as a built-in value, but in which the built-in of that name is also needed. For example, in a module that wants to implement an open() function that wraps the built-in open(), this module can be used directly:

import builtins

def open(path):
    f = builtins.open(path, 'r')
    return UpperCaser(f)

class UpperCaser:
    '''Wrapper around a file that converts output to upper-case.'''

    def __init__(self, f):
        self._f = f

    def read(self, count=-1):
        return self._f.read(count).upper()

However in your case there seems to be no classmethod definition in the file so you don't actually need the from builtins import classmethod.