Option definition store 
option=maximumImageSize
displayName=Maximum image size?
type=ByteSizeOption
unit=kb
defaultValue=10
maxValue=10000
Option store 
maximumImageSize=100
Option semantics 
class ByteSizeOption(IntegerOption):
   def printEditControl(self):
       IntegerOption.printEditControl(self)
       print self.getUnitAbbreviation()

   def getUnitAbbreviation(self):
       return self.unit
+User interface 
class ConfigurationCGI(BaseCGI):

     def processRequest():
         ...
Configuration framework
Maximum image size? kb