code: def set_env_or_defaults(self):
          
          option = namedtuple('Option', ['section', 'name', 'env_var',
                                         'default_value'])
  
          options = [option('auth', 'user', 'NAPPS_USER', None),
                     option('auth', 'token', 'NAPPS_TOKEN', None),
                     option('napps', 'api', 'NAPPS_API_URI',
                            'https://napps.kytos.io/api/'),
                     option('napps', 'repo', 'NAPPS_REPO_URI',
                            'https://napps.kytos.io/repo'),
                     option('kytos', 'api', 'KYTOS_API',
                            'http://localhost:8181/')]
  
          for option in options:
              if not self.config.has_option(option.section, option.name):
                  env_value = os.environ.get(option.env_var,
                                             option.default_value)
                  if env_value:
                      self.config.set(option.section, option.name, env_value)
  
          self.config.set('global', 'debug', str(self.debug))
docs: Read some environment variables and set them on the config.
  
          If no environment variable is found and the config section/key is
          empty, then set some default values.