Class method responsible for adding a code cell with content 'content' to the
        Notebook object.

        ----------
        Parameters
        ----------
        content : str
            Code in a string format to include in the cell (triple quote for multiline
            text).

        tags : list
            A list of tags to include in the code cell metadata.

def add_code_cell(self, content, tags=None):
        """
        Class method responsible for adding a code cell with content 'content' to the
        Notebook object.

        ----------
        Parameters
        ----------
        content : str
            Code in a string format to include in the cell (triple quote for multiline
            text).

        tags : list
            A list of tags to include in the code cell metadata.
        """
        self.notebook["cells"].append(nb.v4.new_code_cell(content, **{"metadata":
                                                                      {"tags": tags}}))