def _verify_include_files_used(self, file_uses, included_files):
for include_file, use in file_uses.items():<EOL><INDENT>if not use & USES_DECLARATION:<EOL><INDENT>node, module = included_files[include_file]<EOL>if module.ast_list is not None:<EOL><INDENT>msg = "<STR_LIT>".format(<EOL>node.filename)<EOL>if use & USES_REFERENCE:<EOL><INDENT>msg += '<STR_LIT>'<EOL><DEDENT>self._add_warning(msg, node)<EOL><DEDENT><DEDENT><DEDENT>
Find all #include files that are unnecessary.