Clean up notebook saving

When saving a notebook, a lot of extra code is generated resulting from interactive matplotlib plots. Every interactive figure saves ~600 lines of unnecessary code. The following snippet strips off any matplotlib output (excluding figures). Furthermore, Additionally, outputs consisting of matplotlib or MatPlot objects are also stripped (these may arise if the last function in a cell returns the figure object).

Place the following snippet in the jupyter notebook config file (~/ .jupyter/jupyter_notebook_config.py). The best to place it is as a replacement of the pre-existing line c.ContentsManager.pre_save_hook

def scrub_output_pre_save(model, **kwargs):
    """scrub output before saving notebooks"""
    # only run on notebooks
    print('scrubbing output before saving')
    if model['type'] != 'notebook':
        return
    # only run on nbformat v4
    if model['content']['nbformat'] != 4:
        return

    for cell in model['content']['cells']:
        if cell['cell_type'] != 'code':
            continue

        # Remove
        filtered_outputs = []
        for output in cell['outputs']:
            javascript_output = output.get('data', {}).get('application/javascript', '')
            plain_output = output.get('data', {}).get('text/plain', '')
            if 'Put everything inside the global mpl namespace' in javascript_output:
                continue
            elif plain_output.startswith('<qcodes.plots.qcmatplotlib.MatPlot'):
                continue
            elif plain_output.startswith('[<matplotlib.'):
                continue
            else:
                filtered_outputs.append(output)
        cell['outputs'] = filtered_outputs
        cell['execution_count'] = None

c.ContentsManager.pre_save_hook = scrub_output_pre_save