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)