
class WebCrawlException(Exception):
	pass

class AuthorNotFoundException(WebCrawlException):
	pass

class DatePublishedNotFoundException(WebCrawlException):
	pass

class TitleNotFoundException(WebCrawlException):
	pass


class WebCrawlException(Exception):
	pass

class AuthorNotFoundException(WebCrawlException):
	pass

class DatePublishedNotFoundException(WebCrawlException):
	pass

class TitleNotFoundException(WebCrawlException):
	pass

class UrlNotFoundException(WebCrawlException):
	pass

Define new exception