'Called by the parser to give the application a locator for
locating the origin of document events.
SAX parsers are strongly encouraged (though not absolutely
required) to supply a locator: if it does so, it must supply
the locator to the application by invoking this method before
invoking any of the other methods in the DocumentHandler
interface.
The locator allows the application to determine the end
position of any document-related event, even if the parser is
not reporting an error. Typically, the application will use
this information for reporting its own errors (such as
character content that does not match an application\'s
business rules). The information returned by the locator is
probably not sufficient for use with a search engine.
Note that the locator will return correct information only
during the invocation of the events in this interface. The
application should not attempt to use it at any other time.'

def setDocumentLocator(self, locator):

    self._locator = locator
