def _traverse_grid_(self):
        for j in reversed(self.j_values):
            for i in range(self.M)[2:]:
                self.grid[i,j] = self.a[i]*self.grid[1-i,j+1] +\
                                 self.b[i]*self.grid[i,j+1] + \
                                 self.c[i]*self.grid[i+1,j+1]
dataset/ETHPy150Open jamesmawm/Mastering-Python-for-Finance-source-codes/B03898_04_codes/FDExplicitEu.py/FDExplicitEu._traverse_grid_/swapped operands of `-`