code: def social_media_profile(self,
                               site: Optional[SocialNetwork] = None) -> str:
          
          key = self._validate_enum(site, SocialNetwork)
          website = SOCIAL_NETWORKS[key]
          url = 'https://www.' + website
          return url.format(self.username())
docs: Generate profile for random social network.
  
          :return: Profile in some network.
  
          :Example:
              http://facebook.com/some_user