使用Python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!'