code: def _waiting_expect(self):
          '''``True`` when the client is waiting for 100 Continue.
          '''
          if self._expect_sent is None:
              if self.environ.get('HTTP_EXPECT', '').lower() == '100-continue':
                  return True
              self._expect_sent = ''
          return Falsf _waiting_expect(self):
          '''``True`` when the client is waiting for 100 Continue.
          '''
          if self._expect_sent is None:
              if self.environ.get('HTTP_EXPECT', '').lower() == '100-continue':
                  return True
              self._expect_sent = ''
          return False
docs: ``True`` when the client is waiting for 100 Continue.