python code(1)

 from collections import UserList
 class MthChianList(UserList):
     def filter(self,predicste):
         return MthChianList(elem for elem in self if predicste(elem))
     def map(self,mapper):
         return MthChianList(mapper(elem) for elem in self)
     def for_each(self,action):
         for elem in self:
             action(elem)
 lt=MthChianList(['A','B','c','d','e','F'])
 lt.filter(str.islower).map(str.upper).for_each(print)