Python plot fails with strange error when using ndarray instead of list

[altavir]

When using python plot examples with np.linspace(...) instead of list literal [...], it fails with json error:

~\Anaconda3\lib\site-packages\beakerx\plot\chart.py in add(self, item)
    222     def add(self, item):
    223         self.chart.add(item)
--> 224         self.model = self.chart.transform()
    225         return self
    226 

~\Anaconda3\lib\site-packages\beakerx\utils.py in transform(self)
     46 
     47     def transform(self):
---> 48         model = json.dumps(self, cls=ObjectEncoder)
     49         return json.loads(model)
     50 

~\Anaconda3\lib\json\__init__.py in dumps(obj, skipkeys, ensure_ascii, check_circular, allow_nan, cls, indent, separators, default, sort_keys, **kw)
    236         check_circular=check_circular, allow_nan=allow_nan, indent=indent,
    237         separators=separators, default=default, sort_keys=sort_keys,
--> 238         **kw).encode(obj)
    239 
    240 

~\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)

~\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,

ValueError: Circular reference detected

[altavir]

Adding tolist() to arguments solves the problem. Seems to be specific ndarray problem.