code: def load_known_hosts(self, filename=None):
  
          
  
          if filename is None:
              filename = os.path.expanduser('~/.ssh/known_hosts')
              try:
                  self._host_keys.load(filename)
              except IOError:
                  # for windows
                  filename = os.path.expanduser('~/ssh/known_hosts')
                  try:
                      self._host_keys.load(filename)
                  except IOError:
                      pass
          else:
              self._host_keys.load(filename)
docs: Load host keys from an openssh :file:`known_hosts`-style file. Can
          be called multiple times.
  
          If *filename* is not specified, looks in the default locations i.e. :file:`~/.ssh/known_hosts` and :file:`~/ssh/known_hosts` for Windows.