code: def _dusty_hosts_config(hosts_specs):
      
      rules =  ''.join(['{} {}\n'.format(spec['forwarded_ip'], spec['host_address']) for spec in hosts_specs])
      return config_file.create_config_section(rules)
docs: Return a string of all host rules required to match
      the given spec. This string is wrapped in the Dusty hosts
      header and footer so it can be easily removed later.