Construct a normsubpath consisting of
normsubpathitems, which is a list of normsubpathitem
instances. If closed is set, the normsubpath will be
closed, thereby appending a straight line segment from the first to
the last point, if it is not already present. All calculations with
the normsubpath are performed with an accuracy of epsilon.
Most normsubpath methods behave like the ones of a
path.
Append the anormsubpathitem to the end of the
normsubpath instance. This is only possible if the
normsubpath is not closed, otherwise an exception is raised.
Extend the normsubpath instances by normsubpathitems,
which has to be a list of normsubpathitem instances. This is
only possible if the normsubpath is not closed, otherwise an
exception is raised.
