Python's exec running in module works but in function not - python-3.x

Question

This works:
import os
import sys
with open('tests.py') as fptr:
script_content = fptr.read()
exec(script_content)
And this not:
def run():
import os
import sys
with open('tests.py') as fptr:
script_content = fptr.read()
exec(script_content)
run()
Result:
Traceback (most recent call last):
File "tmp.py", line 8, in <module>
run()
File "tmp.py", line 6, in run
exec(script_content)
File "<string>", line 15, in <module>
File "<string>", line 16, in PlaceSpitter
NameError: name 'Place' is not defined
Could anyone tell my why and how to fix it?

Answer 1

I've read again - carrefully - python's docs especially this one:
Remember that at module level, globals and locals are the same dictionary
And try this:
def run():
import os
import sys
with open('tests.py') as fptr:
script_content = fptr.read()
exec(script_content, globals())
run()
which now works!
I still don't know why but now at least it works.