old_contents: """
  This package contains core modules and classes for representing structures and
  operations on them.
  """
  
  __author__ = "Shyue Ping Ong"
  __date__ = "Dec 15, 2010 7:21:29 PM"
  
  from .periodic_table import *
  from .composition import *
  from .structure import *
  from .structure_modifier import *
  from .bonds import *
  from .lattice import *
  from .sites import *
  from .operations import *
  
new_contents: """
  This package contains core modules and classes for representing structures and
  operations on them.
  """
  
  __author__ = "Shyue Ping Ong"
  __date__ = "Dec 15, 2010 7:21:29 PM"
  
  from .periodic_table import *
  from .composition import *
  from .structure import *
  from .structure_modifier import *
  from .bonds import *
  from .lattice import *
  from .sites import *
  from .operations import *
  from .units import *
subject: Add units to Core import.