`print` does not output in the playground if it has an `separator`-option

[TobiasNx]

See:

https://metafacture.org/playground/?flux=%22https%3A//raw.githubusercontent.com/gbv/Catmandu-Tutorial/master/data/marc.mrc%22%0A%7C+open-http%0A%7C+as-lines%0A%7C+print%28separator%3D%22%22%29%0A%3B

[TobiasNx]

Same is true for header option:

https://metafacture.org/playground/?flux=%22https%3A//raw.githubusercontent.com/gbv/Catmandu-Tutorial/master/data/marc.mrc%22%0A%7C+open-http%0A%7C+as-lines%0A%7C+print%28header%3D%22TEST%22%29%0A%3B