new_contents: # Useful unit conversions
  
  def days(s):
      '''Assume s is time in seconds and a positive integer or float.
      Return time in days'''
      days = s / (60 * 60 * 24) 
      return days
  
  def secs(d):
      '''Assume d is time in days and a positive integer or float.
      Return time in seconds'''
      secs = (60 * 60 * 24) * d
      return secs
  
  def year(d):
      '''Assume d is time in days and a positive integer or float.
      Return time in years'''
      year = 365.25 / d
      return year
  
  def mPerS(mPerD):
      '''Assume mPerD is a positive integer or float.
      Return mPerS'''
      mPerS = days(mPerD)
      return mPerS
  
  def mPerD(mPerS):
      '''Assume mPerS is a positive integer or float.
      Return mPerD'''
      mPerD = secs(mPerS)
      return mPerD
  
subject: Create conversion.py