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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def add_source_files( self, source_filenames_or_globs: Union[str, List[str]], method: AutodocMethod = None, recursive: bool = None, source_rst_title_style_python: bool = None, pygments_language_override: Dict[str, str] = None) -> None: """ Adds source files to the index. Args: source_filenames_or_globs: string containing a filename or a glob, describing the file(s) to be added, or a list of such strings method: optional method to override ``self.method`` recursive: use :func:`glob.glob` in recursive mode? (If ``None``, the default, uses the version from the constructor.) source_rst_title_style_python: optional to override ``self.source_rst_title_style_python`` pygments_language_override: optional to override ``self.pygments_language_override`` """

        if not source_filenames_or_globs:
            return

        if method is None:
            # Use the default
            method = self.method
        if recursive is None:
            recursive = self.recursive
        if source_rst_title_style_python is None:
            source_rst_title_style_python = self.source_rst_title_style_python
        if pygments_language_override is None:
            pygments_language_override = self.pygments_language_override

        # Get a sorted list of filenames
        final_filenames = self.get_sorted_source_files(
            source_filenames_or_globs,
            recursive=recursive
        )

        # Process that sorted list
        for source_filename in final_filenames:
            self.files_to_index.append(FileToAutodocument(
                source_filename=source_filename,
                project_root_dir=self.project_root_dir,
                python_package_root_dir=self.python_package_root_dir,
                target_rst_filename=self.specific_file_rst_filename(
                    source_filename
                ),
                method=method,
                source_rst_title_style_python=source_rst_title_style_python,
                pygments_language_override=pygments_language_override,
            ))