Remove any raw cells from the Notebook.

        By default, exclude raw cells from the output. Change this by including
        global_content_filter->include_raw = True in the resources dictionary.
        This preprocessor is necessary because the NotebookExporter doesn't
        include the exclude_raw config.

def preprocess(
        self, nb: "NotebookNode", resources: dict
    ) -> Tuple["NotebookNode", dict]:
        """Remove any raw cells from the Notebook.

        By default, exclude raw cells from the output. Change this by including
        global_content_filter->include_raw = True in the resources dictionary.
        This preprocessor is necessary because the NotebookExporter doesn't
        include the exclude_raw config."""
        if not resources.get("global_content_filter", {}).get("include_raw", False):
            keep_cells = []
            for cell in nb.cells:
                if cell.cell_type != "raw":
                    keep_cells.append(cell)

            nb.cells = keep_cells

        return nb, resources