Python if文　or分岐がたくさんある場合

# !/user/bin/env python
def main():
    list = [i for i in range(10)]
    print(list)  # [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]

    for i in list:
        if i == 1:
            print('a:{}'.format(i))
        elif i == 2:
            print('a:{}'.format(i))
        elif i == 3:
            print('a:{}'.format(i))
        else:
            print(i)

    """
    0
    a:1
    a:2
    a:3
    4
    5
    6
    7
    8
    9
    """

    for i in list:
        if i in {1, 2, 3}:
            print('a:{}'.format(i))
        else:
            print(i)
    """
    0
    a:1
    a:2
    a:3
    4
    5
    6
    7
    8
    9
    """
if __name__ == '__main__':
    main()