more units.

        :param units:   Which journald units to collect
        :type units: ``str`` or a ``list`` of strings

        :param boot:    A boot index using the journalctl syntax. The special
                        values 'this' and 'last' are also accepted.
        :type boot: ``str``

        :param since:   Start time for journal messages
        :type since: ``str``

        :param until:   End time forjournal messages
        :type until: ``str``

        :param lines: The maximum number of lines to be collected
        :type lines: ``int``

        :param allfields: Include all journal fields regardless of size or
                          non-printable characters
        :type allfields: ``bool``

        :param output:  Journalctl output control string, for example "verbose"
        :type output: ``str``

        :param timeout: An optional timeout in seconds
        :type timeout: ``int``

        :param identifier: An optional message identifier
        :type identifier: ``str``

        :param catalog: Augment lines with descriptions from the system catalog
        :type catalog: ``bool``

        :param sizelimit: Limit to the size of output returned in MB.
                          Defaults to the value of --log-size.
        :type sizelimit: ``int``
        z