code: def __prefix_key(self, key):
          
          # If there isn't a prefix don't bother
          if self.prefix is None:
              return key
  
          # Don't prefix key if it already has it
          if key.startswith(self.prefix + "-"):
              return key
  
          return "{0}-{1}".format(self.prefix, key)
docs: This will add the prefix to the key if one exists on the store