FileNameUnset

This error means that you tried to save a Node, but initialized it with raw data and never set a filename. To fix this, see Changing the active file, or set the filename parameter on the save function to save temporarily (see Saving).

Here's an example:

x = Node()
x.get('test')
# or
x.test

Output:

You have not specified a filename for this data.
Try setting the filename parameter or use switch_to_file.