# Module: `nbformat.v4.convert`

Code for converting notebooks to and from v3.

## 10 Functions

`IPython.nbformat.v4.convert.``upgrade`(nb, from_version=3, from_minor=0)

  Convert a notebook to v4.

  Parameters:

  nb : NotebookNode

  > The Python representation of the notebook to convert.

  from_version : int

  > The original version of the notebook to convert.

  from_minor : int

  > The original minor version of the notebook to convert (only relevant for v >= 3).

`IPython.nbformat.v4.convert.``upgrade_cell`(cell)

  upgrade a cell from v3 to v4

  heading cell -> markdown heading code cell:

  > - remove language metadata
  > - cell.input -> cell.source
  > - cell.prompt_number -> cell.execution_count
  > - update outputs

`IPython.nbformat.v4.convert.``downgrade_cell`(cell)

  downgrade a cell from v4 to v3

  code cell:
    - set cell.language
    - cell.input <- cell.source
    - cell.prompt_number <- cell.execution_count
    - update outputs
  markdown cell:
    - single-line heading -> heading cell

`IPython.nbformat.v4.convert.``to_mime_key`(d)

  convert dict with v3 aliases to plain mime-type keys

`IPython.nbformat.v4.convert.``from_mime_key`(d)

  convert dict with mime-type keys to v3 aliases

`IPython.nbformat.v4.convert.``upgrade_output`(output)

  upgrade a single code cell output from v3 to v4

  - pyout -> execute_result
  - pyerr -> error
  - output.type -> output.data.mime/type
  - mime-type keys
  - stream.stream -> stream.name

`IPython.nbformat.v4.convert.``downgrade_output`(output)

  downgrade a single code cell output to v3 from v4

  - pyout <- execute_result
  - pyerr <- error
  - output.data.mime/type -> output.type
  - un-mime-type keys
  - stream.stream <- stream.name

`IPython.nbformat.v4.convert.``upgrade_outputs`(outputs)

  upgrade outputs of a code cell from v3 to v4

`IPython.nbformat.v4.convert.``downgrade_outputs`(outputs)

  downgrade outputs of a code cell to v3 from v4

`IPython.nbformat.v4.convert.``downgrade`(nb)

  Convert a v4 notebook to v3.

  Parameters:

  nb : NotebookNode

  > The Python representation of the notebook to convert.