Palindrome debugging

Rather than simply list all of the commonly useful PDB commands, we're going to instead debug a simple function. Our function – is_palindrome() – takes in an integer and determines if the digits of the integer are a palindrome or not. A palindrome is a sequence which is the same both forwards and backwards.

The first thing we'll do is create a new file, palindrome.py, with this code:

import unittest

def digits(x):
    """Convert an integer into a list of digits.

    Args:
      x: The number whose digits we want.

    Returns: A list of the digits, in order, of ``x``.

    >>> digits(4586378)
    [4, 5, 8, 6, 3, 7, 8]
    """

    digs = []
    while x != 0:
        div, mod = divmod(x, 10)
        digs.append(mod)
        x = mod
    return digs

def is_palindrome(x):
    """Determine if an integer...