code: def _assertion(self, assertion, verified=False):
          
  
          if not hasattr(assertion, 'signature') or not assertion.signature:
              logger.debug("unsigned")
              if self.require_signature:
                  raise SignatureError("Signature missing for assertion")
          else:
              logger.debug("signed")
              if not verified and self.do_not_verify is False:
                  try:
                      self.sec.check_signature(assertion, class_name(assertion),
                                               self.xmlstr)
                  except Exception as exc:
                      logger.error("correctly_signed_response: %s", exc)
                      raise
  
          self.assertion = assertion
          logger.debug("assertion context: %s", self.context)
          logger.debug("assertion keys: %s", assertion.keyswv())
          logger.debug("outstanding_queries: %s", self.outstanding_queries)
  
          # if self.context == "AuthnReq" or self.context == "AttrQuery":
          if self.context == "AuthnReq":
              self.authn_statement_ok()
          # elif self.context == "AttrQuery":
          #            self.authn_statement_ok(True)
  
          if not self.condition_ok():
              raise VerificationError("Condition not OK")
  
          logger.debug("--- Getting Identity ---")
  
          # if self.context == "AuthnReq" or self.context == "AttrQuery":
          #    self.ava = self.get_identity()
          #    logger.debug("--- AVA: %s", self.ava)
  
          try:
              self.get_subject()
              if self.asynchop:
                  if self.allow_unsolicited:
                      pass
                  elif self.came_from is None:
                      raise VerificationError("Came from")
              return True
          except Exception:
              logger.exception("get subject")
              raise
docs: Check the assertion
          :param assertion:
          :return: True/False depending on if the assertion is sane or not