ValueError: 'w:val' Invalid Attribute Name in Microsoft Word XML

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, use a valid attribute name for the 'val' attribute. Consult the Microsoft Word XML specification or the relevant documentation for your XML library to find the correct attribute name.