In Python variables in a program which may not be accessible at all locations in python program. This depends on where you have declared a variable and value.
The scope of a variable determines the portion of the program using which we can access a particular identifier and variable. There are two basic scopes of variables in Python to given below
Global variables-
Local variables- And for example you can see below code-

# Function definition is here
def sum( arg1, arg2 ):
   # Add both the parameters and return them."
   total = arg1 + arg2; # Here total is local variable.
   print "Inside the function local total : ", total
   return total;
# Now you can call sum function
sum( 40, 60 );
print "Outside the function global total : ", total 

And output-
Inside the function local total :100
Outside the function global total :0