<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:

def rar(rarfile, sources, template=None, cwd=None, runas=None):
    '''
    Uses `rar for Linux`_ to create rar files

    .. _`rar for Linux`: http://www.rarlab.com/

    rarfile
        Path of rar file to be created

    sources
        Comma-separated list of sources to include in the rar file. Sources can
        also be passed in a Python list.

        .. versionchanged:: 2017.7.0
            Globbing is now supported for this argument

    cwd : None
        Run the rar command from the specified directory. Use this argument
        along with relative file paths to create rar files which do not
        contain the leading directories. If not specified, this will default
        to the home directory of the user under which the salt minion process
        is running.

        .. versionadded:: 2014.7.1

    template : None
        Can be set to 'jinja' or another supported template engine to render
        the command arguments before execution:

        .. code-block:: bash

            salt '*' archive.rar template=jinja /tmp/rarfile.rar '/tmp/sourcefile1,/tmp/{{grains.id}}.txt'

    CLI Example:

    .. code-block:: bash

        salt '*' archive.rar /tmp/rarfile.rar /tmp/sourcefile1,/tmp/sourcefile2
        # Globbing for sources (2017.7.0 and later)
        salt '*' archive.rar /tmp/rarfile.rar '/tmp/sourcefile*'
    '''
    cmd = ['rar', 'a', '-idp', '{0}'.format(rarfile)]
    cmd.extend(_expand_sources(sources))
    return __salt__['cmd.run'](cmd,
                               cwd=cwd,
                               template=template,
                               runas=runas,
                               python_shell=False).splitlines()