old_contents: """
  Constants, or objects with constant values, that are used by other modules.
  """
  
  Y_COLUMNS = ['solids', 'lighttars', 'heavytars', 'totaltars', 'CO', 'CO2',
               'othergases', 'totalgases', 'H20', 'H-C-ratio', 'Moisture',
               'tot_C--O', 'tot_aromaticC-O', 'tot_aromaticC-C',
               'tot_aromaticC-H', 'tot_aliphaticC-O', 'tot_aromatic_methoxyl',
               'tot_aliphaticC-C', 'heavy_C--O', 'heavy_aromatic_C-O',
               'heavy_aromatic_C-C', 'heavy_aromatic_C-H', 'heavy_aliphatic_C-O',
               'heavy_aromatic_methoxyl', 'heavy_aliphatic_C-C', 'light_C--O',
               'light_aromatic_C-O', 'light_aromatic_C-H',
               'light_aliphatic_C-O', 'light_aliphatic_C-C']
  
new_contents: """
  Constants, or objects with constant values, that are used by other modules.
  """
  
  Y_COLUMNS = ['solids', 'lighttars', 'heavytars', 'totaltars', 'CO', 'CO2',
               'othergases', 'totalgases', 'H20', 'H-C-ratio', 'Moisture',
               'tot_C--O', 'tot_aromatic_C-O', 'tot_aromatic_C-C',
               'tot_aromatic_C-H', 'tot_aliphatic_C-O', 'tot_aromatic_methoxyl',
               'tot_aliphatic_C-C', 'heavy_C--O', 'heavy_aromatic_C-O',
               'heavy_aromatic_C-C', 'heavy_aromatic_C-H', 'heavy_aliphatic_C-O',
               'heavy_aromatic_methoxyl', 'heavy_aliphatic_C-C', 'light_C--O',
               'light_aromatic_C-O', 'light_aromatic_C-H',
               'light_aliphatic_C-O', 'light_aliphatic_C-C']
  
subject: correct typo in labels