index errors

[ridgerunnersjw]

Can someone please tell what I am doing wrong??...I am continually getting an index error. I have a 4x2x3 matrix (lists) and I am trying to first create a list containing three lists and then as a final step I would like to reduce this to one list....I test lengths out in the command line so I do not understand why I am getting these index errors....
what would the solution look like in list comprehension?

thanks

import random
def m():
	c = []; tmpa = []; tmpb = []
	c.append([[[random.randint(0,4) for i in range(2)] for k in range(4)] for i in range(3)])
	for i in range(2):
		tmpa = []
		for j in range(4):
			tmpb = []
			for k in range(2):
				p = sum(c[i][j][k])
			tmpb.append(p)
		tmpb.append(tmpa)
	return(c)

Error:
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/home/pi/myPython/test.py", line 10, in m
    p = sum(c[i][j][k])
IndexError: list index out of range