scope - How to understand dynamic scoping using Python code? -

i'm programmer coming python background typically uses lexical scoping , want understand dynamic scope. i've researched on-line, still unclear me. example, i've read this page made things lot easier me, code snippets:

#in dynamic scoping:              const int b = 5;             int foo()                    {                               int = b + 5;        return a;     }      int bar()     {        int b = 2;        return foo();     }      int main()     {        foo(); // returns 10        bar(); // returns 7        return 0;     }   #in lexical scoping:              const int b = 5;             int foo()                    {                               int = b + 5;        return a;     }      int bar()     {        int b = 2;        return foo();     }      int main()     {        foo(); // returns 10        bar(); // returns 10        return 0;     } 

as understand , can see, in dynamic scoping, bar function returns 7 not 10, means foo called b variable defined within bar, in other words, foo did not looked b variable that's defined in top of code (the first b variable) rather used b variables that's defined in bar.

q1: hence, in dynamic scoping, function that's being called within function in case foo called in bar first looks variables in caller function in case bar , looks top level variables ?

q2: explain dynamic scoping in python code ?

there no dynamic scoping in python, unless implement own stack-based 'namespace'.

and yes, dynamic scoping simple; value of variable determined closest calling namespace value set. view calls stack, , value looked searching current call stack top bottom.

so dynamic example, stack first:

foo main  globals -> b = 5 

finding b = 5 when searching through stack, , stack changes to

foo bar -> b = 2 main globals -> b = 5 

so b = 2 found.