code: def nestKey(self, key):
      '''Returns a nested `key`.'''
  
      nest = self.nest_keyfn(key)
  
      # if depth * length > len(key.name), we need to pad.
      mult = 1 + int(self.nest_depth * self.nest_length / len(nest))
      nest = nest * mult
  
      pref = Key(self.nestedPath(nest, self.nest_depth, self.nest_length))
      return pref.child(keyf nestKey(self, key):
      '''Returns a nested `key`.'''
  
      nest = self.nest_keyfn(key)
  
      # if depth * length > len(key.name), we need to pad.
      mult = 1 + int(self.nest_depth * self.nest_length / len(nest))
      nest = nest * mult
  
      pref = Key(self.nestedPath(nest, self.nest_depth, self.nest_length))
      return pref.child(key)
docs: Returns a nested `key`.