3-Write a Python program that has subprograms nested four deep and in which each nested subprogram references local variables, variables defined in all of its enclosing subprograms, and global variables.

Explanation:

Below is a little explanation to guide us through;

There are 4 nested methods : level 0, level 1, level 2, and level 3.

Before the methods, there's a global variable defined that can be accessed by all the methods.

Level 0:

This method uses global variable, creates a level 0 variable in its scope, this level 0 variable can be used by all underlying nested methods.

Level 1: this method uses global, level 0, and level 1 variable, which can be accessed by all underlying nested methods: level 2, level 3.

Level 2: similar to te previous ones, it also uses global, level 0, level 1 variables. And creates a level 2 variable that can be accessed by level 3 also.

Level 3:

This method uses all previously created variables, and creates a new level 3 variable.

Function calls:

As you can see, the function calls are part of the method scopes. So, in order to call level 3, we need to access level 2 (because it is getting called from level 2 scope), for level 2, we must call level 1, for which level 0 needs to be called.

So, level 0 is called, which gives its out put and calls level 1, which gives its own output and calls level 2 and so on till level 3 is also called.

CODE:

global_var = "global" #accessible to all functions

def level0():

level0_var = "level 0" #accessible to level 0,1,2,3

print();

print("Level 0 function:")

print("global variable: ",global_var)

print("local variable 0: ",level0_var)

def level1():

print();

print("Level 1 function:")

level1_var = "level 1" ##accessible to level 1,2,3

print("global variable: ",global_var)

print("local variable 0: ",level0_var)

print("local variable 1: ",level1_var)

def level2():

print();

print("Level 2 function:")

level2_var = "level 2" #accessible to level 2,3

print("global variable: ",global_var)

print("local variable 0: ",level0_var)

print("local variable 1: ",level1_var)

print("local variable 2: ",level2_var)

def level3():

print();

print("Level 3 function:")

level3_var = "level 3" #accessible to level 3

print("global variable: ",global_var)

print("local variable 0: ",level0_var)

print("local variable 1: ",level1_var)

print("local variable 2: ",level2_var)

print("local variable 3: ",level3_var)

level3()

level2()

level1()

level0()

attached is the result of the code, also take note of the indentations too

cheers i hope this helps