import sys

class Std(object):

    """ makes top-level python modules available as an attribute,

        importing them on first access.

    """

    def __init__(self):

        self.__dict__ = sys.modules

    def __getattr__(self, name):

        try:

            m = __import__(name)

        except ImportError:

            raise AttributeError("py.std: could not import %s" % name)

        return m

std = Std()