# changed ValueError to ImportError
Code cleaning.
Fixed inconsistencies in ImportError handling. Sometimes it raises
ImportError and sometime ValueError.
I've changed all cases to the `raise ImportError`
Also:
- added installation instruction in the error message, where it missed;
- fixed several installation instructions in the error message;
- fixed several error handling in regards to the ImportError
`NotebookLoader.load()` loads the `.ipynb` notebook file into a
`Document` object.
**Parameters**:
* `include_outputs` (bool): whether to include cell outputs in the
resulting document (default is False).
* `max_output_length` (int): the maximum number of characters to include
from each cell output (default is 10).
* `remove_newline` (bool): whether to remove newline characters from the
cell sources and outputs (default is False).
* `traceback` (bool): whether to include full traceback (default is
False).
Leonid Ganeline