code: def from_string(address):
  		
  		if len(address) == 0:
  			return WFQDN()
  
  		if address[-1] == '.':
  			address = address[:-1]
  
  		if len(address) > WFQDN.maximum_fqdn_length:
  			raise ValueError('Invalid address')
  
  		result = WFQDN()
  		for label in address.split('.'):
  			if isinstance(label, str) and WFQDN.re_label.match(label):
  				result._labels.append(label)
  			else:
  				raise ValueError('Invalid address')
  
  		return result
docs: Convert doted-written FQDN address to WFQDN object
  
  		:param address: address to convert
  		:return: WFQDN