Follow this example to create a variable outside functions, and use it inside the functions:

MyVariable = 99 #this is a global variable

def changeAndPrint_GlobalVariable():
    global MyVariable  #use global variable in this function with "global" keyword
    print('Global variable "MyVariable" before change = ', MyVariable) # the global variable is printed
    MyVariable = 1  #change the value of the global variable is printed
    print('Global variable "MyVariable" after change = ', MyVariable) # the global variable is printed

def changeAndPrint_LocalVariable():
    MyVariable = 77 #this is a local variable
    print('Local variable "MyVariable" = ', MyVariable) #the local variable is printed

changeAndPrint_GlobalVariable() #call the function
changeAndPrint_LocalVariable() #call the function

This code will print:

Global variable "MyVariable" before change =  99
Global variable "MyVariable" after change =  1
Local variable "MyVariable" =  77