code: def values_from_env(env_prefix, settable, booleans, repeatable):
      
      defaults_env = dict()
      for key in settable:
          try:
              defaults_env[key] = get_env(key, env_prefix, key in booleans, key in repeatable)
          except KeyError:
              pass
      return defaults_env
docs: Get all values from environment variables.
  
      :param str env_prefix: Argument from docoptcfg().
      :param iter settable: Option long names available to set by config file.
      :param iter booleans: Option long names of boolean/flag types.
      :param iter repeatable: Option long names of repeatable options.
  
      :return: Settable values.
      :rtype: dict