#The 'Walrus' operator does not support multiple assignment but does not #flag an attempt to make a multiple assigment as an error
#This results in unexpected behavior at execution time:

a, b = 100, 200

print (a, b)
#result is
#100 200

if (a, b := 3, 4): #this should be flagged as an error but is not



  print ("found true")
else:
  print ("found false")

print (a, b)
#result is
#100 3 but if multiple assigment were allowed this would be '3, 4'


----------------------------------------------------------------------
Python 3.9.0 (tags/v3.9.0:9cf6752, Oct  5 2020, 15:34:40) [MSC v.1927 64 bit (AMD64)] on win32
Type "help", "copyright", "credits" or "license()" for more information.
>>> 
= RESTART: C:\Users\John PC 2017\AppData\Local\Programs\Python\Python38-32\walrustest.py
100 200
found true
100 3
>>>

Due to the precedence of the walrus operator, it is not actually a multiple assignment but rather a tuple of 3 elements with one being the value of the assignment expression.

 $ python -m ast  
(a, b := 3, 4)
Module(
   body=[
      Expr(
         value=Tuple(
            elts=[
               Name(id='a', ctx=Load()),
               NamedExpr(
                  target=Name(id='b', ctx=Store()),
                  value=Constant(value=3)),
               Constant(value=4)],
            ctx=Load()))],
   type_ignores=[])

In this case, it creates a tuple with loading the name `a` from the current scope, using the value of the 3 and also assigning 3 to the b, and loading constant 4.

So basically (a, b := 3, 4) is actually (a, (b := 3), 4)