old_contents: """
  
  Define the common units, in the array of powers form.
  
  Copyright 2012, Casey W. Stark. See LICENSE.txt for more information.
  
  """
  
  from sympy.core import Integer
  
  from dimensionful.dimensions import *
  from dimensionful.units import Unit, unit_symbols_dict
  
  # cgs base units
  g  = Unit("g")
  cm = Unit("cm")
  s  = Unit("s")
  K  = Unit("K")
  
  # other cgs
  dyne = Unit("dyne")
  erg  = Unit("erg")
  esu  = Unit("esu")
  
  # SI stuff
  m = Unit("m")
  
  # times
  minute = Unit("min")  # can't use `min` because of Python keyword :(
  hr = Unit("hr")
  day = Unit("day")
  yr = Unit("yr")
  
  # solar units
  Msun = Unit("Msun")
  Rsun = Unit("Rsun")
  Lsun = Unit("Lsun")
  Tsum = Unit("Tsun")
  
  # astro distances
  AU = Unit("AU")
  pc = Unit("pc")
  ly = Unit("ly")
  
new_contents: """
  
  Define some common units, so users can import the objects directly.
  
  Copyright 2012, Casey W. Stark. See LICENSE.txt for more information.
  
  """
  
  from sympy.core import Integer
  
  from dimensionful.dimensions import *
  from dimensionful.units import Unit, unit_symbols_dict
  
  # cgs base units
  g  = Unit("g")
  cm = Unit("cm")
  s  = Unit("s")
  K  = Unit("K")
  
  # other cgs
  dyne = Unit("dyne")
  erg  = Unit("erg")
  esu  = Unit("esu")
  
  # SI stuff
  m = Unit("m")
  
  # times
  minute = Unit("min")  # can't use `min` because of Python keyword :(
  hr = Unit("hr")
  day = Unit("day")
  yr = Unit("yr")
  
  # solar units
  Msun = Unit("Msun")
  Rsun = Unit("Rsun")
  Lsun = Unit("Lsun")
  Tsum = Unit("Tsun")
  
  # astro distances
  AU = Unit("AU")
  pc = Unit("pc")
  ly = Unit("ly")
  
subject: Update top-of-file docstring.