environment/lib/python2.7/site-packages/IPython/nbformat/v3/rwbase.py
def restore_bytes(nb):
    """Restore bytes of image data from unicode-only formats.
    
    Base64 encoding is handled elsewhere.  Bytes objects in the notebook are
    always b64-encoded. We DO NOT encode/decode around file formats.
    """
    for ws in nb.worksheets:
        for cell in ws.cells:
            if cell.cell_type == 'code':
                for output in cell.outputs:
                    if 'png' in output:
                        output.png = str_to_bytes(output.png, 'ascii')
                    if 'jpeg' in output:
                        output.jpeg = str_to_bytes(output.jpeg, 'ascii')
    return nb
def restore_bytes(nb):
    """Restore bytes of image data from unicode-only formats.
    
    Base64 encoding is handled elsewhere.  Bytes objects in the notebook are
    always b64-encoded. We DO NOT encode/decode around file formats.
    """
    for ws in nb.worksheets:
        for cell in ws.cells:
            if cell.cell_type == 'code':
                for output in cell.outputs:
                    if 'png' in output:
                        output.png = str_to_bytes(output.png, 'ascii')
                    if 'jpeg' in output:
                        output.jpeg = str_to_bytes(output.jpeg, 'ascii')
    return nb
Restore bytes of image data from unicode-only formats.
    
    Base64 encoding is handled elsewhere.  Bytes objects in the notebook are
    always b64-encoded. We DO NOT encode/decode around file formats.