def create_file(filename):
expanded_filename = os.path.expanduser(os.path.expandvars(filename))<EOL>if not os.path.exists(expanded_filename):<EOL><INDENT>open(expanded_filename, "<STR_LIT:a>").close()<EOL><DEDENT>
Creates a new file if the file name does not exists
:param filename: the name of the file