@utilities.arguments_not_none<EOL><INDENT>def add_vtt_file(self, vtt_file, language_type=None):<DEDENT>
if not isinstance(vtt_file, DataInputStream):<EOL><INDENT>raise InvalidArgument('<STR_LIT>')<EOL><DEDENT>locale = DEFAULT_LANGUAGE_TYPE.identifier<EOL>if language_type is not None:<EOL><INDENT>locale = language_type.identifier<EOL><DEDENT>self.my_osid_object_form.add_file(vtt_file,<EOL>locale,<EOL>asset_name="<STR_LIT>",<EOL>asset_description="<STR_LIT>")<EOL>
Adds a vtt file tagged as the given language.

        arg:    vtt_file (displayText): the new vtt_file
        raise:  InvalidArgument - ``vtt_file`` is invalid
        raise:  NoAccess - ``Metadata.isReadOnly()`` is ``true``
        raise:  NullArgument - ``media_description`` is ``null``
        *compliance: mandatory -- This method must be implemented.*