#!/usr/local/bin/python2
from abc import abstractmethod
from collections import Container, Iterable, Mapping, Sequence, Sized
from array import array


class Array(Sized, Iterable, Container):
    __slots__ = ()
    __methods = '__getitem__', '__contains__', '__iter__', '__len__'

    @abstractmethod
    def __getitem__(self, key):
        raise KeyError

    def __contains__(self, value):
        return any(v == value for v in self)

    @classmethod
    def __subclasshook__(cls, C):
        if cls is Array and all(hasattr(C, method) for method in cls.__methods):
            return True
        return NotImplemented