Can somebody help me understand why the following code fails?

def foo(code):
    exec(code)


if __name__ == "__main__":
    code = R"""
from typing import List
class Test:
    def __init__(a: List):
        pass
    """
    foo(code)
    # exec(code)  # this works

I’m using Python 3.9.19 on MacOs.
Also, the following changes make the example work:

• Replacing List with list
• running exec(code) before foo
• passing globals() as locals to exec
• changing the code to:

code = R"""
from typing import List
def boo(a: List):
    pass
"""

The code example to run without error.