1了解python2和python3类的区别
    python2在2.4之前使用的是经典类, 2.4之后, 使用的是新式类

    class Foo:
        pass

    class Foo(object):
        pass

    MRO: method resolution order 方法的查找顺序

    class Base:
        pass

    class Base1:
        def chi():
            pass

    class Bar(Base, Base1):
        pass

    b = Bar() # Bar -> Base -> Base1
    b.chi()


2. 经典类的MRO 树形结构的深度优先遍历 -> 树形结构遍历

3. 新式类的MRO C3算法(难点, 重点)
    1. 拆分
    2. 合并

    用头和身体比较
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class A:
    pass
class B(A):
    pass
class C(A):
    pass
class D(B, C):
    pass
class E(C, A):
    pass
class F(D, E):
    pass
class M:
    pass
class N(M):
    pass
class P(E, A):
    pass
class X:
    pass
class Q(P,N,X):
    pass
class G(Q, F):
    pass
class H(G, F):
    pass
 
# L(A) = A
# L(B) = B + L(A) + A
# L(C) = C + L(A) + A
# L(D) = D + L(B) + L(C) + BC
# L(E) = E + L(C) + L(A) + CA
# L(F) = F + L(D) + L(E) + DE
# L(M) = M
# L(N) = N + L(M) + M
# L(P) = P + L(E) + L(A) + EA
# L(X) = X
# L(Q) = Q + L(P) + L(N) + L(X) +PNX
# L(G) = G + L(Q) + L(F) + QF
# L(H) = H + L(G) + L(F) + GF
#
#
# L(A) = A
# L(B) = B + L(A) + A             # BA
# L(C) = C + L(A) + A             # CA
# L(D) = D + L(B) + L(C) + BC     # DBCA
# L(E) = E + L(C) + L(A) + CA     # ECA
# L(F) = F + L(D) + L(E) + DE     # FDBECA
# L(M) = M
# L(N) = N + L(M) + M             # NM
# L(P) = P + L(E) + L(A) + EA     # PECA
# L(X) = X
# L(Q) = Q + L(P) + L(N) + L(X) +PNX  # QPECANMX
# L(G) = G + L(Q) + L(F) + QF     # GQPFDBECANMX
# L(H) = H + L(G) + L(F) + GF     # HGQPFDBECANMX