'Save the current workbook under the given `filename`.
Use this function instead of using an `ExcelWriter`.
.. warning::
When creating your workbook using `write_only` set to True,
you will only be able to call this function once. Subsequents attempts to
modify or save the file will raise an :class:`openpyxl.shared.exc.WorkbookAlreadySaved` exception.'

def save(self, filename):

    if self.read_only:
        raise TypeError('Workbook    is    read-only')
    if self.write_only:
        save_dump(self, filename)
    else:
        save_workbook(self, filename)
