'Add a vbaProject binary to the Excel workbook.
Args:
vba_project: The vbaProject binary file name.
is_stream:   vba_project is an in memory byte stream.
Returns:
Nothing.'

def add_vba_project(self, vba_project, is_stream=False):

    if ((not is_stream) and (not os.path.exists(vba_project))):
        warn(("VBA    project    binary    file    '%s'    not    found." % force_unicode(vba_project)))
        return (-1)
    self.vba_project = vba_project
    self.vba_is_stream = is_stream
