A variable's scope is the part of a program where the variable can be accessed. A variable created outside of a function has global scope and can be accessed anywhere in the program. A Python program begins in global scope, and the global scope lasts for the entire program execution.
Local scope
A variable created within a function has local scope and only exists within the function. A local variable cannot be accessed outside of the function in which the variable was created. After a function finishes executing, the function's local variables no longer exist.
Using local and global variables together
Python allows global and local variables to have the same name, which can lead to unexpected program behavior. A function treats a variable edited within the function as a local variable unless told otherwise. To edit a global variable inside a function, the variable must be declared with the global keyword.
