Python detecting error in code

Question

This snippet of python code has a lot of errors, but I wanted to know if someone can specifically explain to me what the "No global traceback found" error and "self is not first method argument?" The following occur on lines 16 and 28 respectively.

 1 #! /usr/bin/env python
 2
 3 'Example errors caught by PyChecker'
 4
 5 import string
 6
 7 metaslash = 1
 8
 9 def printNames():
10 neal = 'neal'
11 michelle = 'michele'
12 eric = 5
13 print "Local values: %(neal)S %(michele)s %(eric)" % locals()
14
15 class Nothing:
16 def printValue(value):
17 print value
18 def set(self, value):
19 self.value = value
20
21 def tryToDoSomething(self, value):
22 try:
23 import string
24 if not value:
25 raise RuntimeError, "Hey, there's no value"
26 printNames('a, b, c')
27 except:
28 traceback.print_exc()
29
30 def setGlobal(value=None):
31 print 'Old MetaSlash value is:', metaslash
32 metaslash = value
33 useless = Nothing(5)
34 print 'a useless value is:', useless.valeu

Answer 1

line 16 should be:

def printValue(self, value):

on line 28, what is this traceback object you are calling from? Python is not finding it.

• python5: Ok, figured it out and get what you're saying. What about line 16?
• Cameron Sparr: On line 16 you forgot the self, which every function within a class needs (see answer)
• Makoto: It doesn't have to be. You could always decorate it with @classmethod to get around that.
• Cameron Sparr: yes that's true, but beginner pythoneers probably shouldn't mess around with decorators
• python5: Can you further explain the use of @classmethod ?