I don't know the cause of Python TypeError. (scipy.optimize)

def func_y(x, a):
    return (1 + a) * x / (a + x) #TypeError: can't multiply sequence by non-int of type 'float'


a = 0.0462

x = [0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0]

y = func_y(x, a)

popt, pcov = curve_fit(func_y,  x,  y)