Python function replacing itself in the module namespace
This question already has an answer here:
If you go without the global statement, you will be creating a local variable with the name _run_wsgi_app , and then will use it, but nothing will change in the global namespace. Using global _run_wsgi_app you ensure that you are re-binding the global name to the new function.
Remember the basic usage of global :
def foo():
x = 2
def bar():
global x
x = 3
x = 1
print(x) # --> 1
foo()
print(x) # --> 1
bar()
print(x) # --> 3
Your example is the same, but instead of binding the name directly with name = ... , it does with from ... import ... as name .
An alternative way to redefine itself without global is to use the module object where it is contained.
def _run_wsgi_app(*args):
from werkzeug.test import run_wsgi_app as new_run_wsgi_app
import sys
sys.modules[__name__]._run_wsgi_app = new_run_wsgi_app
return new_run_wsgi_app(*args)