code: def from_line(cls, line, lineno=None):
          
          log = get_logger('paramiko.hostkeys')
          fields = line.split(' ')
          if len(fields) < 3:
              # Bad number of fields
              log.info("Not enough fields found in known_hosts in line %s (%r)" %
                       (lineno, line))
              return None
          fields = fields[:3]
  
          names, keytype, key = fields
          names = names.split(',')
  
          # Decide what kind of key we're looking at and create an object
          # to hold it accordingly.
          try:
              key = b(key)
              if keytype == 'ssh-rsa':
                  key = RSAKey(data=decodebytes(key))
              elif keytype == 'ssh-dss':
                  key = DSSKey(data=decodebytes(key))
              elif keytype == 'ecdsa-sha2-nistp256':
                  key = ECDSAKey(data=decodebytes(key))
              else:
                  log.info("Unable to handle key of type %s" % (keytype,))
                  return None
  
          except binascii.Error as e:
              raise InvalidHostKey(line, e)
  
          return cls(names, key)
docs: Parses the given line of text to find the names for the host,
          the type of key, and the key data. The line is expected to be in the
          format used by the OpenSSH known_hosts file.
  
          Lines are expected to not have leading or trailing whitespace.
          We don't bother to check for comments or empty lines.  All of
          that should be taken care of before sending the line to us.
  
          :param str line: a line from an OpenSSH known_hosts file