bottomElementsetwval none ValueError Invalid attribute name wval

This error occurs because 'w:val' is not a valid attribute name.

In Microsoft Word's XML format, attributes must follow a specific naming convention. The attribute name must start with a letter or underscore and can be followed by any number of letters, digits, underscores, hyphens, or periods. However, the attribute name cannot start with the characters 'xml', 'xmlns', or 'xsi'.

To fix this error, you should use a valid attribute name for the 'val' attribute. You can consult the Microsoft Word XML specification or the relevant documentation for your XML library to find the correct attribute name