btmgmt doesn't wanna be redirected

output

peter@doosje /tmp> ./test.py
normal stdout (should be empty):
Index list with 1 item
hci0:	Primary controller
	addr 9C:FC:E8:F2:41:6B version 10 manufacturer 2 class 0x3c0104
	supported settings: powered connectable fast-connectable discoverable bondable link-security ssp br/edr hs le advertising secure-conn debug-keys privacy configuration static-addr phy-configuration wide-band-speech 
	current settings: powered ssp br/edr le secure-conn 
	name doosje
	short name 
hci0:	Configuration options
	supported options: public-address 
	missing options: 
end of normal stdout


redirected stdout:
Hello World!

redirected stderr:

peter@doosje /tmp> 

test.py

#!/bin/env python3

import sys, io, btmgmt

print('normal stdout (should be empty):')

ogo = sys.stdout
oge = sys.stderr
sys.stdout = io.StringIO()
sys.stderr = io.StringIO()

print('Hello World!')
btmgmt.command('info')

o = sys.stdout
e = sys.stderr
sys.stdout = ogo
sys.stderr = oge
o.seek(0)
e.seek(0)

print('end of normal stdout\n\n')
print('redirected stdout:')
print(o.read())
print('redirected stderr:')
print(e.read())