def buildRow(self,x,y):
        '''
        Method for private use only.
        '''
        row = [1.0]
        for o in range(1,self.order+1):
            for i in range(o+1):
                row.append(float(x)**i*float(y)**(i-o))
        return row
dataset/ETHPy150Open bolme/pyvision/src/pyvision/vector/Polynomial.py/Polynomial2D.buildRow/swapped operands of `-`