+ """Find all the bigrams in a method to be enciphered.
+
+ If both letters are the same, the `padding_letter` is used instead of the
+ second letter. If `padding_replaces_repeat` is `True`, the `padding_letter`
+ replaces the second letter of the bigram. If `padding_replaces_repeat` is
+ `False`, the second letter of this bigram becomes the first letter of the
+ next, effectively lengthening the message by one letter.
+ """