using dis to look inside code

this example from a Well House Consultants training course
More on this [link]

This example is described in the following article(s):
• Disassembling Python and Java - previously compiled code - [link]

Source code: lookin Module: Y150

""" The dis method in the dis class allows you to disassemble your Python code -
to see what's going on internally. Here's an example of code that's been written
which is then run and diassembled: """

import dis

def average(* collect):
    global count
    sofar = 0
    count = 0
    for val in collect:
        sofar += val
        count += 1
    try:
        avg = sofar / float(count)
        return avg
    except:
        raise

a1 = average(4,6,4)
print a1
print "average of",count

try:
    a2 = average()
except:
    print "Not possible"
print "average of",count

dis.dis(average)

""" Sample Output:

munchkin:oxpy grahamellis$ python lookin
4.66666666667
average of 3
Not possible
average of 0
10 0 LOAD_CONST 1 (0)
              3 STORE_FAST 1 (sofar)

11 6 LOAD_CONST 1 (0)
              9 STORE_GLOBAL 0 (count)

12 12 SETUP_LOOP 34 (to 49)
             15 LOAD_FAST 0 (collect)
             18 GET_ITER
        >> 19 FOR_ITER 26 (to 48)
             22 STORE_FAST 2 (val)

13 25 LOAD_FAST 1 (sofar)
             28 LOAD_FAST 2 (val)
             31 INPLACE_ADD
             32 STORE_FAST 1 (sofar)

14 35 LOAD_GLOBAL 0 (count)
             38 LOAD_CONST 2 (1)
             41 INPLACE_ADD
             42 STORE_GLOBAL 0 (count)
             45 JUMP_ABSOLUTE 19
        >> 48 POP_BLOCK

15 >> 49 SETUP_EXCEPT 24 (to 76)

16 52 LOAD_FAST 1 (sofar)
             55 LOAD_GLOBAL 1 (float)
             58 LOAD_GLOBAL 0 (count)
             61 CALL_FUNCTION 1
             64 BINARY_DIVIDE
             65 STORE_FAST 3 (avg)

17 68 LOAD_FAST 3 (avg)
             71 RETURN_VALUE
             72 POP_BLOCK
             73 JUMP_FORWARD 10 (to 86)

18 >> 76 POP_TOP
             77 POP_TOP
             78 POP_TOP

19 79 RAISE_VARARGS 0
             82 JUMP_FORWARD 1 (to 86)
             85 END_FINALLY
        >> 86 LOAD_CONST 0 (None)
             89 RETURN_VALUE
munchkin:oxpy grahamellis$

"""

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