You haven’t imported dateutil.parser. You can see it, but you have to somehow import it.
>>> import dateutil.parser
>>> dateutil.parser.parse("01-02-2013")
datetime.datetime(2013, 1, 2, 0, 0)
That’s because the parser.py is a module in the dateutil package. It’s a separate file in the folder structure.
Answer to the question you asked in the comments, the reason why relativedelta and tz appear in the namespace after you’ve from dateutil import parser is because parser itself imports relativedelta and tz.
If you look at the source code of dateutil/parser.py, you can see the imports.
# -*- coding:iso-8859-1 -*-
"""
Copyright (c) 2003-2007 Gustavo Niemeyer <gustavo@niemeyer.net>
This module offers extensions to the standard Python
datetime module.
"""
... snip ...
from . import relativedelta
from . import tz