Ascii85 encoding-decoding

ascii85.py

from itertools import groupby

def split_list(alist,max_size=1):
	"""Yield successive n-sized chunks from l."""
	for i in range(0, len(alist), max_size):
		yield alist[i:i+max_size]

def toAscii85(data):
	result = []
	for chunk in split_list(data, max_size=4):
		# print(chunk)#debug
		n_missing_chars = 4-len(chunk)
		chunk += chr(0)*n_missing_chars
		mult = sum(ord(i)*(256**n) for n, i in enumerate(reversed(chunk)))
		# print(mult)#debug

		templist = []
		for _ in range(5):
			temp = divmod(mult,85)
			templist.append(chr(temp[1]+33))
			mult = temp[0]

		# print(templist)#debug

		if all(i=="!" for i in templist) and not n_missing_chars:
			result.append("z")
		else:
			result.extend(templist[::-1])

		if n_missing_chars:
			result = result[:-n_missing_chars]

	return "<~" + "".join(result) + "~>"
	
def fromAscii85(data):
	data = "".join(data[2:-2].split())#split() knows all the whitedata chars, so I don't have to input them
	# print "data", data#debug

	result = []
	for bigger_grouped_chunk in groupby(data,key=lambda x: x=='z'):
		print("bigger_grouped_chunk", bigger_grouped_chunk)#debug
		if bigger_grouped_chunk[0]:
			result.append(chr(0)*(4*sum(1 for _ in bigger_grouped_chunk[1])))
		else:
			for chunk in split_list(list(bigger_grouped_chunk[1]), max_size=5):
				# print("chunk",chunk)#debug
				n_missing_chars = 5-len(chunk)
				chunk =  chunk +["u"]*n_missing_chars
				mult = sum((ord(i)-33)*(85**n) for n, i in enumerate(reversed(chunk)))

				# print(mult)#debug

				templist = []
				for _ in range(4):
					temp = divmod(mult,256)
					templist.append(chr(temp[1]))
					mult = temp[0]

				# print(templist)#debug

				result.extend(templist[::-1])

				if n_missing_chars:
					result = result[:-n_missing_chars]


	return "".join(result)

# print(toAscii85('easy'))
# print(toAscii85('moderate'))
# print(toAscii85('somewhat difficult'))
# print(toAscii85('\x00'))

# print(fromAscii85("<~ARTY*~>"))
# print(fromAscii85('<~F)Po,GA(E,+Co1uAnbatCif~>'))
# print(list(fromAscii85('<~zz~>')))
print(list(fromAscii85("<~;f?Ma+92BAz!!$qJA0:jPzz!!!\"FATD^#F!(G_zz!,,qaAK_~>")))