Return |False| if there is a ``<w:tblLayout>`` child with ``w:type``
        attribute set to ``'fixed'``. Otherwise return |True|.

def autofit(self):
        """
        Return |False| if there is a ``<w:tblLayout>`` child with ``w:type``
        attribute set to ``'fixed'``. Otherwise return |True|.
        """
        tblLayout = self.tblLayout
        if tblLayout is None:
            return True
        return False if tblLayout.type == 'fixed' else True