def help(self, error=None, topic=None, parser=None):
assert error or topic or parser<EOL>if error:<EOL><INDENT>print(error)<EOL>print("<STR_LIT>")<EOL><DEDENT>elif parser:<EOL><INDENT>print(parser.format_help().strip())<EOL><DEDENT>else:<EOL><INDENT>help_msg = HELP_TOPICS.get(topic, '<STR_LIT>').strip()<EOL>if help_msg:<EOL><INDENT>print(help_msg % self.covpkg.__dict__)<EOL><DEDENT>else:<EOL><INDENT>print("<STR_LIT>" % topic)<EOL><DEDENT><DEDENT>
Display an error message, or the named topic.