Error message in Jupyter Notebook with json

[diet]

Hi,

I am new to Python and Jupyter Notebook and I get the error below in Jupyter Notebook while the code works in Spyder:

import base64
import json
import subprocess

def output_image(name, format, bytes):
    image_start = "BEGIN_IMAGE_f9825uweof8jw9fj4r8"
    image_end = "END_IMAGE_0238jfw08fjsiufhw8frs"
    data = {}
    data['name'] = name
    data['format'] = format
    data['bytes'] = base64.encodestring(bytes)
    print(image_start + json.dumps(data) + image_end)

Error:
TypeError                                 Traceback (most recent call last)
<ipython-input-16-f9e8ef7a162f> in <module>()
      1 ### draw the decision boundary with the text points overlaid
      2 instanceCV.prettyPicture(clf, features_test, labels_test)
----> 3 instanceCV.output_image("test.png", "png", open("test.png", "rb").read())

<ipython-input-10-99476019b17b> in output_image(self, name, format, bytes)
     71         data['format'] = format
     72         data['bytes'] = base64.encodestring(bytes)
---> 73         print(image_start + json.dumps(data) + image_end)

C:\ProgramData\Anaconda3\lib\json\__init__.py in dumps(obj, skipkeys, ensure_ascii, check_circular, allow_nan, cls, indent, separators, default, sort_keys, **kw)
    229         cls is None and indent is None and separators is None and
    230         default is None and not sort_keys and not kw):
--> 231         return _default_encoder.encode(obj)
    232     if cls is None:
    233         cls = JSONEncoder

C:\ProgramData\Anaconda3\lib\json\encoder.py in encode(self, o)
    197         # exceptions aren't as detailed.  The list call should be roughly
    198         # equivalent to the PySequence_Fast that ''.join() would do.
--> 199         chunks = self.iterencode(o, _one_shot=True)
    200         if not isinstance(chunks, (list, tuple)):
    201             chunks = list(chunks)

C:\ProgramData\Anaconda3\lib\json\encoder.py in iterencode(self, o, _one_shot)
    255                 self.key_separator, self.item_separator, self.sort_keys,
    256                 self.skipkeys, _one_shot)
--> 257         return _iterencode(o, 0)
    258 
    259 def _make_iterencode(markers, _default, _encoder, _indent, _floatstr,

Thanks for help