Choir 1
=======

A choir has stored the information of its singers in a :class:`list`
of tuples (:class:`tuple`). Each tuple has three elements: the name
(:class:`str`), the voice (:class:`str`) that can be soprano, alto,
tenor or bass, and a Boolean (:class:`bool`) showing whether the
singer can act as a soloist (``True``) or not (``False``).

Save the following functions into the same file ``choir.py``

#. Write the function :py:func:`singers_dict` that takes a list as
   described, and returns a dictionary (:class:`dict`) in which keys
   are voices and values are lists of two elements: the number of
   singers with that voice (:class:`int`) and the number of singers
   with that voice that can act as soloists (:class:`int`). The
   dictionary must be complete taking into account the four mentioned
   voices. Example:
   
   .. literalinclude:: test-singers.txt
      :language: python
      :lines: 3-11

   .. note::

      You can download the file with tests 
      :download:`test-singers.txt <test-singers.txt>`.

#. This choir has a dictionary for each musical piece of their
   repertoire with a structure similar to the dictionary computed in
   the previous function: keys are voices and values are lists of two
   elements: the number of singers with that voice and the number of
   soloists with that voice which are needed in this musical piece.

   Write the function :py:func:`feasible` that takes two dictionaries:
   a dictionary with the choir singers and a dictionary corresponding
   to a musical piece, and returns a Boolean (:class:`bool`) with the
   value of ``True`` if the choir has enough singers and soloists of
   each voice to represent this piece and ``False``
   otherwise. Example:

   .. literalinclude:: test-feasible.txt
      :language: python
      :lines: 3-

   .. note::

      You can download the file with tests
      :download:`test-feasible.txt <test-feasible.txt>`.


.. rubric:: Solutions

You have some solutions in file :download:`choir.py
<solutions/choir.py>`.