def list(path, keys=()):
        """
        Retrieve information about the given path.

        If the path represents a non-directory, the result list should
        have only one entry with information about that non-directory.
        Otherwise, the result list should have an element for each
        child of the directory.

        @param path: The path, as a list of segments, to list
        @type path: C{list} of C{unicode} or C{bytes}

        @param keys: A tuple of keys desired in the resulting
        dictionaries.

        @return: A Deferred which fires with a list of (name, list),
        where the name is the name of the entry as a unicode string or
        bytes and each list contains values corresponding to the requested
        keys.  The following are possible elements of keys, and the
        values which should be returned for them:

            - C{'size'}: size in bytes, as an integer (this is kinda required)

            - C{'directory'}: boolean indicating the type of this entry

            - C{'permissions'}: a bitvector (see os.stat(foo).st_mode)

            - C{'hardlinks'}: Number of hard links to this entry

            - C{'modified'}: number of seconds since the epoch since entry was
              modified

            - C{'owner'}: string indicating the user owner of this entry

            - C{'group'}: string indicating the group owner of this entry
        """

        Retrieve information about the given path.

        If the path represents a non-directory, the result list should
        have only one entry with information about that non-directory.
        Otherwise, the result list should have an element for each
        child of the directory.

        @param path: The path, as a list of segments, to list
        @type path: C{list} of C{unicode} or C{bytes}

        @param keys: A tuple of keys desired in the resulting
        dictionaries.

        @return: A Deferred which fires with a list of (name, list),
        where the name is the name of the entry as a unicode string or
        bytes and each list contains values corresponding to the requested
        keys.  The following are possible elements of keys, and the
        values which should be returned for them:

            - C{'size'}: size in bytes, as an integer (this is kinda required)

            - C{'directory'}: boolean indicating the type of this entry

            - C{'permissions'}: a bitvector (see os.stat(foo).st_mode)

            - C{'hardlinks'}: Number of hard links to this entry

            - C{'modified'}: number of seconds since the epoch since entry was
              modified

            - C{'owner'}: string indicating the user owner of this entry

            - C{'group'}: string indicating the group owner of this entry
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/protocols/ftp.py