UnboundLocalError: local variable 'license_b64' referenced before assignment

[mbch331]

I tried to get the key for a video from npostart.nl
First I got an error that token couldn't be found.
I copied the value from tokenID from params
Then provider was missing, added a line for that too
Then releasePid was missing, set that to an empty sting.
This is the resulting headers.py
headers.py.txt

Then I got this error:

Traceback (most recent call last):
  File "/home/remko/dev/python/widevine_keys/l3.py", line 130, in <module>
    correct, keys = WV_Function(pssh, lic_url)
  File "/home/remko/dev/python/widevine_keys/l3.py", line 125, in WV_Function
    wvdecrypt.update_license(license_b64)
UnboundLocalError: local variable 'license_b64' referenced before assignment