code: def common(self, other):
  		'''
  			Find the shared part of two multipliers. This is the largest multiplier
  			which can be safely subtracted from both the originals. This may
  			return the "zero" multiplier.
  		'''
  		mandatory = min(self.mandatory, other.mandatory)
  		optional = min(self.optional, other.optional)
  		return multiplier(mandatory, mandatory + optionalf common(self, other):
  		'''
  			Find the shared part of two multipliers. This is the largest multiplier
  			which can be safely subtracted from both the originals. This may
  			return the "zero" multiplier.
  		'''
  		mandatory = min(self.mandatory, other.mandatory)
  		optional = min(self.optional, other.optional)
  		return multiplier(mandatory, mandatory + optional)
docs: Find the shared part of two multipliers. This is the largest multiplier
  			which can be safely subtracted from both the originals. This may
  			return the "zero" multiplier.