Get the function variable in decorator

I have a function and a decorator function,

def decorator(func):
  def wrapper(*args, **kwargs):
    res = func(*args, **kwargs)
    print(func.x)
    return res 
  return wrapper

@decorator
def add(a, b):
  x = "hello"
  c = a + b
  return c

but this would not print the variable x, how do I get the variable x in the decorator?