Explicitly importing an attribute from a module into the current namespace means that the value of that attribute will not be updated if the value in the original module changes.

This can mean that changes in global state are not observed locally, which may lead to inconsistencies and possible errors.

Instead of using from module import attr, simply import the module using import module and replace all uses of attr with module.attr.

In the first of the two modules shown below, from sys import stdout is used to import the stdout attribute, rather than using import sys to import the module. Then stdout is used in the main() function.

In the second module, below, a function, redirect_to_file is defined to collect the output from sys.stdout and save it to a file. However, redirect_to_file will not work correctly when passed the main() function. This is because the main() function will not see the change to sys.stdout, as it uses its own version of stdout that was defined when the module was loaded.

The problem can be fixed by rewriting the first module to import the sys module and write to sys.stdout, as shown below.

Python Language Reference: The import statement.

Python Tutorial: Modules.