SR2019-Buggy-Code

# Implementation of a bubble sort.
# This code is syntactically correct, however there are a couple of
# problems that prevent it from producing the desired output.
# Find these errors and correct them, writing a comment explaining
# what the error was.

def swap_values(i1, i2, list_):
    list_[i1], list_[i2] = list_[i1], list_[i1]
    return list_

def sort(values):
    for pass_num in range(1, len(values)):
        pass_size = len(values) - pass_num
        for i in range(pass_size + 1):
            if values[i] > values[i + 1]:
                values = swap_values(i, i, values)
    return values

print sort([3, 45, 212, 31, 53, 4])