old_contents: # Copyright (c) Paul R. Tagliamonte <tag@pault.ag>, 2015
  #
  # Permission is hereby granted, free of charge, to any person obtaining a
  # copy of this software and associated documentation files (the "Software"),
  # to deal in the Software without restriction, including without limitation
  # the rights to use, copy, modify, merge, publish, distribute, sublicense,
  # and/or sell copies of the Software, and to permit persons to whom the
  # Software is furnished to do so, subject to the following conditions:
  # 
  # The above copyright notice and this permission notice shall be included in
  # all copies or substantial portions of the Software.
  # 
  # THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  # IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  # FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  # THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  # LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  # FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
  # DEALINGS IN THE SOFTWARE.
  
  from .tone import Tone
  from .scale import SEMITONE
  
  MAJOR = [0, SEMITONE * 4, SEMITONE * 7]
  MINOR = [0, SEMITONE * 3, SEMITONE * 7]
  
  MAJOR_7TH = [0, SEMITONE * 4, SEMITONE * 7, SEMITONE * 11]
  MINOR_7TH = [0, SEMITONE * 3, SEMITONE * 7, SEMITONE * 10]
  
  
  def chord(tone, pattern):
      return [tone.relative_tone(x) for x in pattern]
  
new_contents: # Copyright (c) Paul R. Tagliamonte <tag@pault.ag>, 2015
  #
  # Permission is hereby granted, free of charge, to any person obtaining a
  # copy of this software and associated documentation files (the "Software"),
  # to deal in the Software without restriction, including without limitation
  # the rights to use, copy, modify, merge, publish, distribute, sublicense,
  # and/or sell copies of the Software, and to permit persons to whom the
  # Software is furnished to do so, subject to the following conditions:
  # 
  # The above copyright notice and this permission notice shall be included in
  # all copies or substantial portions of the Software.
  # 
  # THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  # IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  # FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  # THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  # LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  # FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
  # DEALINGS IN THE SOFTWARE.
  
  from .tone import Tone
  from .scale import SEMITONE
  
  MAJOR = [0, SEMITONE * 4, SEMITONE * 7]
  MINOR = [0, SEMITONE * 3, SEMITONE * 7]
  
  MAJOR_7TH = [0, SEMITONE * 4, SEMITONE * 7, SEMITONE * 11]
  MAJOR_7TH_DIM = [0, SEMITONE * 3, SEMITONE * 6, SEMITONE * 11]
  
  MINOR_7TH = [0, SEMITONE * 3, SEMITONE * 7, SEMITONE * 10]
  DIM_7TH = [0, SEMITONE * 3, SEMITONE * 6, SEMITONE * 9]
  
  
  
  def chord(tone, pattern):
      return [tone.relative_tone(x) for x in pattern]
  
subject: Add more.