code: def CROSS(A, B):
      
  
      var = np.where(A < B, 1, 0)
      return (pd.Series(var, index=A.index).diff() < 0).apply(int)
docs: A<B then A>B  A上穿B B下穿A
  
      Arguments:
          A {[type]} -- [description]
          B {[type]} -- [description]
  
      Returns:
          [type] -- [description]