'Return a :class:`.Template` object corresponding to the given
``uri``.
The default implementation raises
:class:`.NotImplementedError`. Implementations should
raise :class:`.TemplateLookupException` if the given ``uri``
cannot be resolved.
:param uri: String URI of the template to be resolved.
:param relativeto: if present, the given ``uri`` is assumed to
be relative to this URI.'

def get_template(self, uri, relativeto=None):

    raise NotImplementedError()
