Getting an unexpected generator object ?

[gontajones]

from scipy import integrate

a=0
b=1
n=500
h=(b-a)/(n)

def f(x):
	return x**2

def trapezoidal(f,a,b,n):
	return (h/2)*(f(a)+f(b))+h*( sum(f(a+h*i)  for i in range(1, (n-1))))

print(trapezoidal(f,a,b,n))

# Why this?
lambda x: f(x)

c= integrate.quad(f,0,1)
print(c)

error=(abs(trapezoidal(f,a,b,n)-c[0]) for n in range (300,900))

for idx, i in enumerate(error):
	print(idx, i)