Palindromes
===========

A word or number is a *palindrome* if it reads the same backwards as forwards, such as the words *madam* or *racecar*, or the numbers 1234321 or 5680865. A single character word o single digit number are always palindromes.

Implement the following Python function in the :mod:`palindromes` module (file :file:`palindromes.py`):

    .. py:function:: gen_palindromes(L)

such that

    **given** `L`, a list of words (:class:`str`)

    **returns**  a list with all the palindrome words that can be obtained by concatenating any two words of `L` in the following terms for the resulting list:
    
        #. It must not contain repetitions.
        #. It must not contain words resulting from concatenating a word with itself.
        #. It can have the correct words in any order.
        
Bear in mind that the order of concatenation is important since a different order may produce a different word.

For example:

.. literalinclude:: gen_palindromes-test.txt
    :language: python
    :start-after: --ex-ini
    :end-before: --ex-fi

Doctests are available at the file :download:`gen_palindromes-test.txt <gen_palindromes-test.txt>`.