code: def get_new_messages(self, domain):
          
          if domain not in self.domains:
              raise ValueError('Invalid domain: {0}'.format(domain))
  
          if domain not in self.messages or 'new' not in self.messages[domain]:
              self._process_domain(domain)
  
          return self.messages[domain]['new']
docs: Returns new valid messages after operation.
          @type domain: str
          @rtype: dict