[Tutor] err in integration

[Msd De]

Dear Sir,
I would like to print the error in numerical calculation.
I get this error
*Traceback (most recent call last):*


*  File "DFF_test.py", line 45, in <module>    print("The numerical result
is {:J1} (+-{:err})".format(J1, err))ValueError: Invalid conversion
specification*

*Here is the code*
import numpy as np
import math
import array as arr
from scipy import integrate

B=38.68
T=10.0/B

IL1=int(501-20*T)
IL2=int(501+20*T)
FF=[]
for i in range(0, IL1+1):
xx=-25.0+(i-1)*0.05
FF.append(-xx)
for i in range(IL1+1, IL2+1):
xx=-25.0+(i-1)*0.05
FF.append(np.log(1+np.exp(-B*xx))/B)
for i in range(IL2+1, 1002):
FF.append(0)

array_FF=np.zeros(1001)
for j in range(1001):
array_FF[int(j)]=(FF[j])
np.savetxt('FF.txt', array_FF, delimiter='  ')

eta1=10.0;evb=3.0
DFFF=[]
def DFF(Ex):
for j in range(64):
x1=Ex[j]-eta1
x2=x1+evb
xI1=501+20*x1
xI2=501+20*x2
NI11=int(xI1)
NI12=int(xI2)
FFxI1=array_FF[NI11]+(xI1-NI11)*(array_FF[NI11+1]-array_FF[NI11])
FFxI2=array_FF[NI12]+(xI2-NI12)*(array_FF[NI12+1]-array_FF[NI12])
DFFF=(FFxI1-FFxI2)
return DFFF

EL = 0.0
EH=10.0
J1, err=integrate.fixed_quad(DFF, EL, EH, n=64)
print("The numerical result is {:J1} (+-{:err})".format(J1, err))