code: def hostname(self, hostname):
          
          if not isinstance(hostname, six.string_types):
              raise TypeError("hostname must be a string.  {0} was passed.".format(type(hostname)))
  
          # if a host name is passed and its not valid raise else set hostname empty strings are the docker default.
          if hostname and not is_valid_hostname(hostname):
              raise ValueError("{0} isn't a valid hostname").format(hostname)
          else:
              self._hostname = hostname
docs: hostname setter