code: def add_tuning(instrument, description, tuning):
      
      t = StringTuning(instrument, description, tuning)
      if _known.has_key(str.upper(instrument)):
          _known[str.upper(instrument)][1][str.upper(description)] = t
      else:
          _known[str.upper(instrument)] = (instrument,
                  {str.upper(description): t})
docs: Add a new tuning to the index.
  
      The instrument and description parameters should be strings; tuning
      should be a list of strings or a list of lists to denote courses.
  
      Example:
      >>> std_strings = ['E-2', 'A-2', 'D-3', 'G-3', 'B-3', 'E-4']
      >>> tuning.add_tuning('Guitar', 'standard', std_strings)
      >>> tw_strings = [['E-2', 'E-3'], ['A-2', 'A-3'], ...........]
      >>> tuning.add_tuning('Guitar', 'twelve string', tw_string)