What is the role and purpose of the 'global' keyword in Python?

The global keyword in Python is used inside a function to indicate that the variable being referenced is in the global scope, not a local variable of the function. This allows modifying the value of a global variable from within the function.

Without global, assigning a value to a variable inside a function creates a new local variable with that name, without affecting the global one.

Example:

x = 10

def increment():
    global x
    x += 1

increment()
print(x)  # Will output 11

If global x is removed, then a local variable x will be created inside the increment function, and the attempt x += 1 will cause an error because the local x is not initialized.