That does not work for me in Python 3.10 or 3.12:

  Python 3.12.2  ...
  Type "help", "copyright", "credits" or "license" for more information.
  >>> def f():
  ...         exec('y = 7') # will still create a local variable
  ...         print(locals()['y']) # will still print this local variable
  ...         print(y) # will still try to access a global variable 'y'
  ...
  >>> f()
  7
  Traceback (most recent call last):
    File "<stdin>", line 1, in <module>
    File "<stdin>", line 4, in f
  NameError: name 'y' is not defined

It does print 7 in Python 2.7.