import mathdef quadratic(a,b,c):    for x in (a,b,c):        if not isinstance(x,(int,float)):            raise TypeError('参数错误')    i=b**2-4*a*c    if i>0:        x1=(-b+math.sqrt(i))/(2*a)        x2=(-b-math.sqrt(i))/(2*a)        print('此方程有两个解：x1=',x1,'x2=', x2)        return x1,x2    elif i==0:        x3=(-b)/(2*a)        print('此方程只有一个解:x1=X2=',x3)        return x3    else:        print('此方程无解')quadratic(2,4,2)quadratic(2,1,2)quadratic('a',1,2)