Does exec("func") convert the inputted function string once or converts it every time the func is called?

More specifically, if I have a code like

exec("a = lambda x:x**2")

>>> a(2)
4
>>> a(3)
9

Will exec be converting the string to a function and evaluating it at the input every time a is called or will it define a as a callable function once and then just refer to it every time a is called after running the exec() function

>Solution :

exec executes the code as if you had typed it yourself into the Python interpreter (or your .py file). You can verify this by adding a print call inside of your exec code:

>>> exec("a = lambda x:x**2; print('running')")
running

>>> a(2)
4

>>> a(9)
81

Notice how running is printed only once.