Python练习-写一个求实数内二次方程解的函数

def quar(a,b,c):
    if not isinstance(a,(int,float))|isinstance(b,(int,float))|isinstance(c,(int,float)):
        raise TypeError('Wrong Type inputing!')
    else:
        from math import sqrt
        tmp1=b**2-4*a*c
        if tmp1>0:
             return '%.04f'%float((-b+sqrt(tmp1))/(2*a)),'%.04f'%((-b-sqrt(tmp1))/(2*a))
        elif tmp1==0:
            return -b/(2*a)
        else:
            return 'No rational answer!'