<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def get_conf_path(filename=None):

 """Return absolute path for configuration file with specified filename."""

    conf_dir = osp.join(get_home_dir(), '.condamanager')

    if not osp.isdir(conf_dir):
        os.mkdir(conf_dir)

    if filename is None:
        return conf_dir
    else:
        return osp.join(conf_dir, filename)