TypeError: b2a_base64() argument 1 must be convertible to a buffer, not ConnectorSession

[jobiols]

Traceback (most recent call last):
  File "/usr/local/lib/python2.7/dist-packages/wdb/ui.py", line 193, in loop
    stop = self.interact()
  File "/usr/local/lib/python2.7/dist-packages/wdb/ui.py", line 240, in interact
    rv = fun(data)
  File "/usr/local/lib/python2.7/dist-packages/wdb/ui.py", line 774, in do_display
    'val': from_bytes(b64encode(thing)),
  File "/usr/lib/python2.7/base64.py", line 54, in b64encode
    encoded = binascii.b2a_base64(s)[:-1]
TypeError: b2a_base64() argument 1 must be convertible to a buffer, not ConnectorSession