Editing Stack trace (section)

=== Python ===
As an example, the following [[Python (programming language)|Python]] program contains an error.
<syntaxhighlight lang="python" line="1" highlight="3,9,13,15">
def a():
    i = 0
    j = b(i)
    return j

def b(z):
    k = 5
    if z == 0:
        c()
    return k + z

def c():
    error()

a()
</syntaxhighlight>
Running the program under the standard Python interpreter produces the following error message.
<syntaxhighlight lang="pytb">
Traceback (most recent call last):
  File "file.py", line 15, in <module>
    a()
  File "file.py", line 3, in a
    j = b(i)
  File "file.py", line 9, in b
    c()
  File "file.py", line 13, in c
    error()
NameError: name 'error' is not defined
</syntaxhighlight>
The stack trace shows where the error occurs, namely in the <code>c</code> function. It also shows that the <code>c</code> function was called by <code>b</code>, which was called by <code>a</code>, which was in turn called by the code on line 15 (the last line) of the program. The activation records for each of these three functions would be arranged in a stack such that the <code>a</code> function would occupy the bottom of the stack and the <code>c</code> function would occupy the top of the stack.