Using the Python regular expression module 're' to search for text patterns. The pattern
we wish to extract is AAAaAAA, a lower-case letter surrounded by 3 upper-case letters
on each side. the re method findall will return all text pattern matches and store them
in a list. So far so good -- now we need to delete all the upper-case letters from
each element in the list and then concatenate the list back into a string.
We used string.translate() to strip out all upper-case letters after converting list
output from re.findall() into a string. The answer we get is not taking us to the
next question, however. Perhaps we don't need to strip out the upper-case letters?