code: def to_host(host, default_protocol='telnet', default_domain=''):
      
      if host is None:
          raise TypeError('None can not be cast to Host')
      if hasattr(host, 'get_address'):
          return host
      if default_domain and not '.' in host:
          host += '.' + default_domain
      return Exscript.Host(host, default_protocol=default_protocol)
docs: Given a string or a Host object, this function returns a Host object.
  
      :type  host: string|Host
      :param host: A hostname (may be URL formatted) or a Host object.
      :type  default_protocol: str
      :param default_protocol: Passed to the Host constructor.
      :type  default_domain: str
      :param default_domain: Appended to each hostname that has no domain.
      :rtype:  Host
      :return: The Host object.