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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:

def _get_pkg_info(*packages, **kwargs):
    '''
    Return list of package information. If 'packages' parameter is empty,
    then data about all installed packages will be returned.

    :param packages: Specified packages.
    :param failhard: Throw an exception if no packages found.
    :return:
    '''
    kwargs = salt.utils.args.clean_kwargs(**kwargs)
    failhard = kwargs.pop('failhard', True)
    if kwargs:
        salt.utils.args.invalid_kwargs(kwargs)

    if __grains__['os'] == 'Ubuntu' and __grains__['osrelease_info'] < (12, 4):
        bin_var = '${binary}'
    else:
        bin_var = '${Package}'

    ret = []
    cmd = "dpkg-query -W -f='package:" + bin_var + "\\n" \
          "revision:${binary:Revision}\\n" \
          "arch:${Architecture}\\n" \
          "maintainer:${Maintainer}\\n" \
          "summary:${Summary}\\n" \
          "source:${source:Package}\\n" \
          "version:${Version}\\n" \
          "section:${Section}\\n" \
          "installed_size:${Installed-size}\\n" \
          "size:${Size}\\n" \
          "MD5:${MD5sum}\\n" \
          "SHA1:${SHA1}\\n" \
          "SHA256:${SHA256}\\n" \
          "origin:${Origin}\\n" \
          "homepage:${Homepage}\\n" \
          "status:${db:Status-Abbrev}\\n" \
          "======\\n" \
          "description:${Description}\\n" \
          "------\\n'"
    cmd += ' {0}'.format(' '.join(packages))
    cmd = cmd.strip()

    call = __salt__['cmd.run_all'](cmd, python_chell=False)
    if call['retcode']:
        if failhard:
            raise CommandExecutionError("Error getting packages information: {0}".format(call['stderr']))
        else:
            return ret

    for pkg_info in [elm for elm in re.split(r"------", call['stdout']) if elm.strip()]:
        pkg_data = {}
        pkg_info, pkg_descr = re.split(r"======", pkg_info)
        for pkg_info_line in [el.strip() for el in pkg_info.split(os.linesep) if el.strip()]:
            key, value = pkg_info_line.split(":", 1)
            if value:
                pkg_data[key] = value
        install_date, install_date_t = _get_pkg_install_time(pkg_data.get('package'), pkg_data.get('arch'))
        if install_date:
            pkg_data['install_date'] = install_date
            pkg_data['install_date_time_t'] = install_date_t  # Unix ticks
        build_date, build_date_t = _get_pkg_build_time(pkg_data.get('package'))
        if build_date:
            pkg_data['build_date'] = build_date
            pkg_data['build_date_time_t'] = build_date_t
        pkg_data['description'] = pkg_descr.split(":", 1)[-1]
        ret.append(pkg_data)

    return ret