Traceback from RSA code when ~/.vomun/keys.json is missing

Traceback (most recent call last):
  File "./tests.py", line 11, in <module>
    from unittests.code.libs.encryption.rsa import *
  File "/home/aj00200/anonplus/aj00200/src/unittests/code/libs/encryption/rsa.py", line 5, in <module>
    import libs.encryption.rsa
  File "/home/aj00200/anonplus/aj00200/src/libs/encryption/rsa.py", line 108, in <module>
    load_keys()
  File "/home/aj00200/anonplus/aj00200/src/libs/encryption/rsa.py", line 62, in load_keys
    print('Key file, %s, could not be loaded.' % sha256)
NameError: global name 'sha256' is not defined