I am trying to build a rudimentary web application involving Bokeh plots in JupyterLab.
In order to make this code in the HoloViews documentation work (and not throw
WARNING:param.RectanglesPlot01428: Tool of type 'box_edit' could not be found and could not be activated by default.), I tried this fix and downgraded to 1.15.4. Unfortunately, this created a different problem.
I used the following Conda environment on a Windows computer:
name: boxStream channels: - conda-forge - defaults - fastai dependencies: - jupyterlab - holoviews<=1.15.4 - panel>=0.12.7 - bokeh - ipywidgets - numpy - nbdev=2.3.12 - fastcore=1.5.28
I ran a cell with import statements and the Bokeh option:
#| export import holoviews as hv from holoviews import opts from holoviews import streams hv.extension('bokeh')
This gave the following error:
WARNING:param.notebook_extension: Holoviews bokeh extension could not be imported, it raised the following exception: ModuleNotFoundError('No module named 'bokeh.models.arrow_heads'') --------------------------------------------------------------------------- ImportError Traceback (most recent call last) Cell In, line 6 3 from holoviews import opts 4 from holoviews import streams ----> 6 hv.extension('bokeh') File ~/anaconda3/envs/boxStream/lib/python3.11/site-packages/pyviz_comms/__init__.py:64, in extension.__new__(cls, *args, **kwargs) 62 except Exception: 63 pass ---> 64 return param.ParameterizedFunction.__new__(cls, *args, **kwargs) File ~/anaconda3/envs/boxStream/lib/python3.11/site-packages/param/parameterized.py:3658, in ParameterizedFunction.__new__(class_, *args, **params) 3656 inst = class_.instance() 3657 inst.param._set_name(class_.__name__) -> 3658 return inst.__call__(*args,**params) File ~/anaconda3/envs/boxStream/lib/python3.11/site-packages/holoviews/ipython/__init__.py:116, in notebook_extension.__call__(self, *args, **params) 114 def __call__(self, *args, **params): 115 comms = params.pop('comms', None) --> 116 super().__call__(*args, **params) 117 # Abort if IPython not found 118 try: File ~/anaconda3/envs/boxStream/lib/python3.11/site-packages/holoviews/util/__init__.py:702, in extension.__call__(self, *args, **params) 697 self.param.warning('%s backend hook %s failed with ' 698 'following exception: %s' % 699 (backend, hook, e)) 701 if selected_backend is None: --> 702 raise ImportError('None of the backends could be imported') 703 Store.set_current_backend(selected_backend) ImportError: None of the backends could be imported
After I could find nothing on this topic and recognizing that there had been a Windows update very recently, I changed my operating system to Linux on a brand new SSD (a project I had been meaning to get around to anyways).
This made no difference and the error recurred. My manager was unable to reproduce this error on macOS but was able to reproduce the error in a Docker container.
This is a relatively undocumented error, but it is seemingly pervasive. Any help?