[Python] Python: Confusing Scope of `exec`

The following code works ok in python

import numpy as np

def foo(a):
b = np.exp(a)
return b

c = foo(1)

print(c)


Using the code inside an exec, it also works ok, no problem:

e = "import numpy as np\n\ndef foo(a):\n b = np.exp(a)\n return b\n\nc = foo(1)\n\nprint(c)"
exec(e)


Using the code inside a nested function, it also works ok, no problem (now the module is imported inside the function):

def bar():
import numpy as np

def foo(a):
b = np.exp(a)
return b

c = foo(1)

print(c)

bar()


However, when I try to create a function to exec the code inside a string, inside a function, as in the code below, it gives me an error:

e = "import numpy as np\n\ndef foo(a):\n b = np.exp(a)\n return b\n\nc = foo(1)\n\nprint(c)"

def baz(s):
exec(s)

baz(e)


Error:

Traceback (most recent call last):
File "...\test.py", line 6, in <module>
baz(e)
File "...\test.py", line 4, in baz
exec(s)
File "<string>", line 7, in <module>
File "<string>", line 4, in foo
NameError: name 'np' is not defined


Why is that?

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