<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def get_authentication_statement(self, subject, ticket):
 """ Build an AuthenticationStatement XML block for a SAML 1.1 Assertion. """

        authentication_statement = etree.Element('AuthenticationStatement')
        authentication_statement.set('AuthenticationInstant',
                                     self.instant(instant=ticket.consumed))
        authentication_statement.set('AuthenticationMethod',
                                     self.authn_method_password)
        authentication_statement.append(subject)
        return authentication_statement