lista = list.sort(lista)
This should be
lista.sort()
The .sort() method is in-place, and returns None. If you want something not in-place, which returns a value, you could use
sorted_list = sorted(lista)
Aside #1: please don’t call your lists list. That clobbers the builtin list type.
Aside #2: I’m not sure what this line is meant to do:
print str("value 1a")+str(" + ")+str("value 2")+str(" = ")+str("value 3a ")+str("value 4")+str("\n")
is it simply
print "value 1a + value 2 = value 3a value 4"
? In other words, I don’t know why you’re calling str on things which are already str.
Aside #3: sometimes you use print("something") (Python 3 syntax) and sometimes you use print "something" (Python 2). The latter would give you a SyntaxError in py3, so you must be running 2.*, in which case you probably don’t want to get in the habit or you’ll wind up printing tuples, with extra parentheses. I admit that it’ll work well enough here, because if there’s only one element in the parentheses it’s not interpreted as a tuple, but it looks strange to the pythonic eye..